From 123d8782950711bcd6d2343302ef1cf8c5914873 Mon Sep 17 00:00:00 2001
From: Harriet Brown <harriet.brown@stfc.ac.uk>
Date: Thu, 5 Mar 2020 08:19:52 +0000
Subject: [PATCH] Repalce header guards in API with pragma once

This commit replaces all header guards in API with #pragma once
---
 Framework/API/inc/MantidAPI/ADSValidator.h                 | 4 +---
 Framework/API/inc/MantidAPI/AlgoTimeRegister.h             | 4 +---
 Framework/API/inc/MantidAPI/Algorithm.h                    | 4 +---
 Framework/API/inc/MantidAPI/AlgorithmFactory.h             | 4 +---
 Framework/API/inc/MantidAPI/AlgorithmFactoryObserver.h     | 4 +---
 Framework/API/inc/MantidAPI/AlgorithmHasProperty.h         | 4 +---
 Framework/API/inc/MantidAPI/AlgorithmHistory.h             | 4 +---
 Framework/API/inc/MantidAPI/AlgorithmManager.h             | 4 +---
 Framework/API/inc/MantidAPI/AlgorithmObserver.h            | 4 +---
 Framework/API/inc/MantidAPI/AlgorithmProperty.h            | 5 +----
 Framework/API/inc/MantidAPI/AlgorithmProxy.h               | 5 +----
 Framework/API/inc/MantidAPI/AnalysisDataService.h          | 4 +---
 Framework/API/inc/MantidAPI/AnalysisDataServiceObserver.h  | 4 +---
 Framework/API/inc/MantidAPI/ArchiveSearchFactory.h         | 4 +---
 Framework/API/inc/MantidAPI/Axis.h                         | 4 +---
 Framework/API/inc/MantidAPI/BinEdgeAxis.h                  | 4 +---
 .../API/inc/MantidAPI/BoostOptionalToAlgorithmProperty.h   | 4 +---
 Framework/API/inc/MantidAPI/BoxController.h                | 4 +---
 Framework/API/inc/MantidAPI/CatalogFactory.h               | 4 +---
 Framework/API/inc/MantidAPI/CatalogManager.h               | 4 +---
 Framework/API/inc/MantidAPI/CatalogSession.h               | 4 +---
 Framework/API/inc/MantidAPI/Citation.h                     | 4 +---
 Framework/API/inc/MantidAPI/Column.h                       | 4 +---
 Framework/API/inc/MantidAPI/ColumnFactory.h                | 4 +---
 Framework/API/inc/MantidAPI/CommonBinsValidator.h          | 4 +---
 Framework/API/inc/MantidAPI/CompositeCatalog.h             | 4 +---
 Framework/API/inc/MantidAPI/CompositeDomain.h              | 4 +---
 Framework/API/inc/MantidAPI/CompositeDomainMD.h            | 4 +---
 Framework/API/inc/MantidAPI/CompositeFunction.h            | 4 +---
 Framework/API/inc/MantidAPI/ConstraintFactory.h            | 4 +---
 Framework/API/inc/MantidAPI/CoordTransform.h               | 4 +---
 Framework/API/inc/MantidAPI/CostFunctionFactory.h          | 4 +---
 Framework/API/inc/MantidAPI/DataProcessorAlgorithm.h       | 4 +---
 Framework/API/inc/MantidAPI/DeclareUserAlg.h               | 4 +---
 Framework/API/inc/MantidAPI/DeprecatedAlgorithm.h          | 4 +---
 Framework/API/inc/MantidAPI/DetectorSearcher.h             | 4 +---
 Framework/API/inc/MantidAPI/DistributedAlgorithm.h         | 4 +---
 Framework/API/inc/MantidAPI/DllConfig.h                    | 5 +----
 Framework/API/inc/MantidAPI/DomainCreatorFactory.h         | 4 +---
 Framework/API/inc/MantidAPI/EnabledWhenWorkspaceIsType.h   | 4 +---
 Framework/API/inc/MantidAPI/EqualBinSizesValidator.h       | 4 +---
 Framework/API/inc/MantidAPI/ExperimentInfo.h               | 4 +---
 Framework/API/inc/MantidAPI/Expression.h                   | 5 +----
 Framework/API/inc/MantidAPI/FileBackedExperimentInfo.h     | 4 +---
 Framework/API/inc/MantidAPI/FileFinder.h                   | 4 +---
 Framework/API/inc/MantidAPI/FileLoaderRegistry.h           | 5 +----
 Framework/API/inc/MantidAPI/FileProperty.h                 | 5 +----
 Framework/API/inc/MantidAPI/FrameworkManager.h             | 5 +----
 Framework/API/inc/MantidAPI/FuncMinimizerFactory.h         | 4 +---
 Framework/API/inc/MantidAPI/FunctionDomain.h               | 5 +----
 Framework/API/inc/MantidAPI/FunctionDomain1D.h             | 4 +---
 Framework/API/inc/MantidAPI/FunctionDomainGeneral.h        | 4 +---
 Framework/API/inc/MantidAPI/FunctionDomainMD.h             | 4 +---
 Framework/API/inc/MantidAPI/FunctionFactory.h              | 4 +---
 Framework/API/inc/MantidAPI/FunctionGenerator.h            | 4 +---
 Framework/API/inc/MantidAPI/FunctionParameterDecorator.h   | 4 +---
 Framework/API/inc/MantidAPI/FunctionProperty.h             | 4 +---
 Framework/API/inc/MantidAPI/FunctionValues.h               | 4 +---
 Framework/API/inc/MantidAPI/GridDomain.h                   | 4 +---
 Framework/API/inc/MantidAPI/GridDomain1D.h                 | 4 +---
 Framework/API/inc/MantidAPI/GroupingLoader.h               | 4 +---
 Framework/API/inc/MantidAPI/HistoWorkspace.h               | 4 +---
 Framework/API/inc/MantidAPI/HistogramValidator.h           | 4 +---
 Framework/API/inc/MantidAPI/HistoryItem.h                  | 4 +---
 Framework/API/inc/MantidAPI/HistoryView.h                  | 4 +---
 Framework/API/inc/MantidAPI/IAlgorithm.h                   | 4 +---
 Framework/API/inc/MantidAPI/IAlgorithm_fwd.h               | 4 +---
 Framework/API/inc/MantidAPI/IArchiveSearch.h               | 5 +----
 Framework/API/inc/MantidAPI/IBackgroundFunction.h          | 4 +---
 Framework/API/inc/MantidAPI/IBoxControllerIO.h             | 4 +---
 Framework/API/inc/MantidAPI/ICatalog.h                     | 4 +---
 Framework/API/inc/MantidAPI/ICatalogInfoService.h          | 4 +---
 Framework/API/inc/MantidAPI/IConstraint.h                  | 4 +---
 Framework/API/inc/MantidAPI/ICostFunction.h                | 4 +---
 Framework/API/inc/MantidAPI/IDomainCreator.h               | 4 +---
 Framework/API/inc/MantidAPI/IEventList.h                   | 4 +---
 Framework/API/inc/MantidAPI/IEventWorkspace.h              | 4 +---
 Framework/API/inc/MantidAPI/IEventWorkspace_fwd.h          | 4 +---
 Framework/API/inc/MantidAPI/IFileLoader.h                  | 4 +---
 Framework/API/inc/MantidAPI/IFuncMinimizer.h               | 4 +---
 Framework/API/inc/MantidAPI/IFunction1D.h                  | 4 +---
 Framework/API/inc/MantidAPI/IFunction1DSpectrum.h          | 4 +---
 Framework/API/inc/MantidAPI/IFunctionGeneral.h             | 4 +---
 Framework/API/inc/MantidAPI/IFunctionMD.h                  | 5 +----
 Framework/API/inc/MantidAPI/IFunctionMW.h                  | 5 +----
 Framework/API/inc/MantidAPI/IFunctionWithLocation.h        | 4 +---
 Framework/API/inc/MantidAPI/IFunction_fwd.h                | 4 +---
 Framework/API/inc/MantidAPI/ILatticeFunction.h             | 4 +---
 Framework/API/inc/MantidAPI/ILiveListener.h                | 4 +---
 Framework/API/inc/MantidAPI/IMDEventWorkspace.h            | 4 +---
 Framework/API/inc/MantidAPI/IMDEventWorkspace_fwd.h        | 4 +---
 Framework/API/inc/MantidAPI/IMDHistoWorkspace.h            | 4 +---
 Framework/API/inc/MantidAPI/IMDHistoWorkspace_fwd.h        | 4 +---
 Framework/API/inc/MantidAPI/IMDIterator.h                  | 4 +---
 Framework/API/inc/MantidAPI/IMDNode.h                      | 4 +---
 Framework/API/inc/MantidAPI/IMDWorkspace.h                 | 4 +---
 Framework/API/inc/MantidAPI/IMaskWorkspace.h               | 4 +---
 Framework/API/inc/MantidAPI/IPawleyFunction.h              | 4 +---
 Framework/API/inc/MantidAPI/IPeakFunction.h                | 4 +---
 Framework/API/inc/MantidAPI/IPeaksWorkspace.h              | 4 +---
 Framework/API/inc/MantidAPI/IPeaksWorkspace_fwd.h          | 4 +---
 Framework/API/inc/MantidAPI/IPowderDiffPeakFunction.h      | 4 +---
 Framework/API/inc/MantidAPI/IRemoteJobManager.h            | 4 +---
 Framework/API/inc/MantidAPI/ISpectrum.h                    | 4 +---
 Framework/API/inc/MantidAPI/ISplittersWorkspace.h          | 4 +---
 Framework/API/inc/MantidAPI/ITableWorkspace.h              | 4 +---
 Framework/API/inc/MantidAPI/ITableWorkspace_fwd.h          | 4 +---
 Framework/API/inc/MantidAPI/ITransformScale.h              | 5 +----
 Framework/API/inc/MantidAPI/IWorkspaceProperty.h           | 4 +---
 Framework/API/inc/MantidAPI/ImmutableCompositeFunction.h   | 4 +---
 Framework/API/inc/MantidAPI/ImplicitFunctionBuilder.h      | 4 +---
 Framework/API/inc/MantidAPI/ImplicitFunctionFactory.h      | 4 +---
 Framework/API/inc/MantidAPI/ImplicitFunctionParameter.h    | 5 +----
 .../API/inc/MantidAPI/ImplicitFunctionParameterParser.h    | 5 +----
 .../inc/MantidAPI/ImplicitFunctionParameterParserFactory.h | 4 +---
 Framework/API/inc/MantidAPI/ImplicitFunctionParser.h       | 4 +---
 .../API/inc/MantidAPI/ImplicitFunctionParserFactory.h      | 4 +---
 Framework/API/inc/MantidAPI/IncreasingAxisValidator.h      | 4 +---
 Framework/API/inc/MantidAPI/IndexProperty.h                | 4 +---
 Framework/API/inc/MantidAPI/IndexTypeProperty.h            | 4 +---
 Framework/API/inc/MantidAPI/InstrumentDataService.h        | 4 +---
 Framework/API/inc/MantidAPI/InstrumentValidator.h          | 4 +---
 Framework/API/inc/MantidAPI/Jacobian.h                     | 4 +---
 Framework/API/inc/MantidAPI/JointDomain.h                  | 4 +---
 Framework/API/inc/MantidAPI/LatticeDomain.h                | 4 +---
 Framework/API/inc/MantidAPI/LinearScale.h                  | 4 +---
 Framework/API/inc/MantidAPI/LiveListener.h                 | 4 +---
 Framework/API/inc/MantidAPI/LiveListenerFactory.h          | 4 +---
 Framework/API/inc/MantidAPI/LogFilterGenerator.h           | 4 +---
 Framework/API/inc/MantidAPI/LogManager.h                   | 4 +---
 Framework/API/inc/MantidAPI/LogarithmScale.h               | 4 +---
 Framework/API/inc/MantidAPI/MDFrameValidator.h             | 4 +---
 Framework/API/inc/MantidAPI/MDGeometry.h                   | 4 +---
 Framework/API/inc/MantidAPI/MatrixWorkspace.h              | 4 +---
 Framework/API/inc/MantidAPI/MatrixWorkspaceMDIterator.h    | 4 +---
 Framework/API/inc/MantidAPI/MatrixWorkspaceValidator.h     | 4 +---
 Framework/API/inc/MantidAPI/MatrixWorkspace_fwd.h          | 4 +---
 Framework/API/inc/MantidAPI/MuParserUtils.h                | 4 +---
 Framework/API/inc/MantidAPI/MultiDomainFunction.h          | 4 +---
 Framework/API/inc/MantidAPI/MultiPeriodGroupAlgorithm.h    | 4 +---
 Framework/API/inc/MantidAPI/MultiPeriodGroupWorker.h       | 4 +---
 Framework/API/inc/MantidAPI/MultipleExperimentInfos.h      | 4 +---
 Framework/API/inc/MantidAPI/MultipleFileProperty.h         | 4 +---
 Framework/API/inc/MantidAPI/NotebookBuilder.h              | 4 +---
 Framework/API/inc/MantidAPI/NotebookWriter.h               | 4 +---
 Framework/API/inc/MantidAPI/NullCoordTransform.h           | 4 +---
 Framework/API/inc/MantidAPI/NumericAxis.h                  | 4 +---
 Framework/API/inc/MantidAPI/NumericAxisValidator.h         | 4 +---
 Framework/API/inc/MantidAPI/OrientedLatticeValidator.h     | 4 +---
 Framework/API/inc/MantidAPI/ParallelAlgorithm.h            | 4 +---
 Framework/API/inc/MantidAPI/ParamFunction.h                | 4 +---
 Framework/API/inc/MantidAPI/ParameterReference.h           | 4 +---
 Framework/API/inc/MantidAPI/ParameterTie.h                 | 4 +---
 Framework/API/inc/MantidAPI/PeakFunctionIntegrator.h       | 4 +---
 Framework/API/inc/MantidAPI/PrecompiledHeader.h            | 4 +---
 Framework/API/inc/MantidAPI/Progress.h                     | 4 +---
 Framework/API/inc/MantidAPI/Projection.h                   | 4 +---
 Framework/API/inc/MantidAPI/RawCountValidator.h            | 4 +---
 Framework/API/inc/MantidAPI/RefAxis.h                      | 4 +---
 Framework/API/inc/MantidAPI/RegisterFileLoader.h           | 4 +---
 Framework/API/inc/MantidAPI/RemoteJobManagerFactory.h      | 4 +---
 .../API/inc/MantidAPI/ResizeRectangularDetectorHelper.h    | 4 +---
 Framework/API/inc/MantidAPI/Run.h                          | 4 +---
 Framework/API/inc/MantidAPI/Sample.h                       | 4 +---
 Framework/API/inc/MantidAPI/SampleShapeValidator.h         | 4 +---
 Framework/API/inc/MantidAPI/SampleValidator.h              | 4 +---
 Framework/API/inc/MantidAPI/ScopedWorkspace.h              | 4 +---
 Framework/API/inc/MantidAPI/ScriptBuilder.h                | 4 +---
 Framework/API/inc/MantidAPI/ScriptRepository.h             | 4 +---
 Framework/API/inc/MantidAPI/ScriptRepositoryFactory.h      | 4 +---
 Framework/API/inc/MantidAPI/SerialAlgorithm.h              | 4 +---
 Framework/API/inc/MantidAPI/SingleCountValidator.h         | 4 +---
 Framework/API/inc/MantidAPI/SingleValueParameter.h         | 5 +----
 Framework/API/inc/MantidAPI/SingleValueParameterParser.h   | 5 +----
 Framework/API/inc/MantidAPI/SpectraAxis.h                  | 4 +---
 Framework/API/inc/MantidAPI/SpectraAxisValidator.h         | 4 +---
 Framework/API/inc/MantidAPI/SpectraDetectorTypes.h         | 4 +---
 Framework/API/inc/MantidAPI/SpectrumDetectorMapping.h      | 5 +----
 Framework/API/inc/MantidAPI/SpectrumInfo.h                 | 4 +---
 Framework/API/inc/MantidAPI/SpectrumInfoItem.h             | 4 +---
 Framework/API/inc/MantidAPI/SpectrumInfoIterator.h         | 4 +---
 Framework/API/inc/MantidAPI/TableRow.h                     | 5 +----
 Framework/API/inc/MantidAPI/TempFunction.h                 | 6 ++----
 Framework/API/inc/MantidAPI/TextAxis.h                     | 5 +----
 Framework/API/inc/MantidAPI/TransformScaleFactory.h        | 4 +---
 Framework/API/inc/MantidAPI/VectorParameter.h              | 4 +---
 Framework/API/inc/MantidAPI/VectorParameterParser.h        | 5 +----
 Framework/API/inc/MantidAPI/Workspace.h                    | 4 +---
 Framework/API/inc/MantidAPI/WorkspaceFactory.h             | 5 +----
 Framework/API/inc/MantidAPI/WorkspaceGroup.h               | 4 +---
 Framework/API/inc/MantidAPI/WorkspaceGroup_fwd.h           | 4 +---
 Framework/API/inc/MantidAPI/WorkspaceHasDxValidator.h      | 4 +---
 Framework/API/inc/MantidAPI/WorkspaceHistory.h             | 4 +---
 .../API/inc/MantidAPI/WorkspaceNearestNeighbourInfo.h      | 4 +---
 Framework/API/inc/MantidAPI/WorkspaceNearestNeighbours.h   | 5 +----
 Framework/API/inc/MantidAPI/WorkspaceOpOverloads.h         | 4 +---
 Framework/API/inc/MantidAPI/WorkspaceProperty.h            | 4 +---
 Framework/API/inc/MantidAPI/WorkspaceUnitValidator.h       | 4 +---
 Framework/API/inc/MantidAPI/Workspace_fwd.h                | 4 +---
 Framework/API/test/ADSValidatorTest.h                      | 4 +---
 Framework/API/test/AlgorithmFactoryObserverTest.h          | 4 +---
 Framework/API/test/AlgorithmFactoryTest.h                  | 4 +---
 Framework/API/test/AlgorithmHasPropertyTest.h              | 4 +---
 Framework/API/test/AlgorithmHistoryTest.h                  | 4 +---
 Framework/API/test/AlgorithmMPITest.h                      | 4 +---
 Framework/API/test/AlgorithmManagerTest.h                  | 4 +---
 Framework/API/test/AlgorithmPropertyTest.h                 | 4 +---
 Framework/API/test/AlgorithmProxyTest.h                    | 4 +---
 Framework/API/test/AlgorithmTest.h                         | 4 +---
 Framework/API/test/AnalysisDataServiceObserverTest.h       | 4 +---
 Framework/API/test/AnalysisDataServiceTest.h               | 4 +---
 Framework/API/test/AsynchronousTest.h                      | 4 +---
 Framework/API/test/BinEdgeAxisTest.h                       | 4 +---
 Framework/API/test/BoxControllerTest.h                     | 4 +---
 Framework/API/test/CitationTest.h                          | 4 +---
 Framework/API/test/CommonBinsValidatorTest.h               | 4 +---
 Framework/API/test/CompositeFunctionTest.h                 | 4 +---
 Framework/API/test/CoordTransformTest.h                    | 4 +---
 Framework/API/test/CostFunctionFactoryTest.h               | 4 +---
 Framework/API/test/DataProcessorAlgorithmTest.h            | 4 +---
 Framework/API/test/DetectorInfoTest.h                      | 4 +---
 Framework/API/test/DetectorSearcherTest.h                  | 4 +---
 Framework/API/test/EnabledWhenWorkspaceIsTypeTest.h        | 4 +---
 Framework/API/test/EqualBinSizesValidatorTest.h            | 4 +---
 Framework/API/test/ExperimentInfoTest.h                    | 4 +---
 Framework/API/test/ExpressionTest.h                        | 4 +---
 Framework/API/test/FakeAlgorithms.h                        | 4 +---
 Framework/API/test/FileBackedExperimentInfoTest.h          | 4 +---
 Framework/API/test/FileFinderTest.h                        | 7 ++-----
 Framework/API/test/FilePropertyTest.h                      | 4 +---
 Framework/API/test/FrameworkManagerTest.h                  | 7 ++-----
 Framework/API/test/FuncMinimizerFactoryTest.h              | 4 +---
 Framework/API/test/FunctionAttributeTest.h                 | 4 +---
 Framework/API/test/FunctionDomainGeneralTest.h             | 4 +---
 Framework/API/test/FunctionDomainTest.h                    | 4 +---
 Framework/API/test/FunctionFactoryTest.h                   | 4 +---
 Framework/API/test/FunctionParameterDecoratorTest.h        | 4 +---
 Framework/API/test/FunctionPropertyTest.h                  | 4 +---
 Framework/API/test/FunctionTest.h                          | 4 +---
 Framework/API/test/FunctionValuesTest.h                    | 4 +---
 Framework/API/test/GroupingLoaderTest.h                    | 4 +---
 Framework/API/test/HistogramValidatorTest.h                | 4 +---
 Framework/API/test/HistoryItemTest.h                       | 4 +---
 Framework/API/test/HistoryViewTest.h                       | 4 +---
 Framework/API/test/IEventListTest.h                        | 4 +---
 Framework/API/test/IFunction1DSpectrumTest.h               | 4 +---
 Framework/API/test/IFunction1DTest.h                       | 4 +---
 Framework/API/test/IFunctionMDTest.h                       | 4 +---
 Framework/API/test/IFunctionTest.h                         | 4 +---
 Framework/API/test/ILatticeFunctionTest.h                  | 4 +---
 Framework/API/test/IMDWorkspaceTest.h                      | 4 +---
 Framework/API/test/ISpectrumTest.h                         | 4 +---
 Framework/API/test/ImmutableCompositeFunctionTest.h        | 4 +---
 Framework/API/test/ImplicitFunctionFactoryTest.h           | 4 +---
 .../API/test/ImplicitFunctionParameterParserFactoryTest.h  | 4 +---
 Framework/API/test/ImplicitFunctionParserFactoryTest.h     | 4 +---
 Framework/API/test/IncreasingAxisValidatorTest.h           | 4 +---
 Framework/API/test/IndexPropertyTest.h                     | 4 +---
 Framework/API/test/IndexTypePropertyTest.h                 | 4 +---
 Framework/API/test/InstrumentDataServiceTest.h             | 4 +---
 Framework/API/test/InstrumentValidatorTest.h               | 4 +---
 Framework/API/test/LatticeDomainTest.h                     | 4 +---
 Framework/API/test/LiveListenerFactoryTest.h               | 4 +---
 Framework/API/test/LiveListenerTest.h                      | 4 +---
 Framework/API/test/LogFilterGeneratorTest.h                | 4 +---
 Framework/API/test/LogManagerTest.h                        | 4 +---
 Framework/API/test/MDFrameValidatorTest.h                  | 4 +---
 Framework/API/test/MDGeometryTest.h                        | 4 +---
 Framework/API/test/MatrixWorkspaceMDIteratorTest.h         | 4 +---
 Framework/API/test/MatrixWorkspaceTest.h                   | 4 +---
 Framework/API/test/MuParserUtilsTest.h                     | 4 +---
 Framework/API/test/MultiDomainFunctionTest.h               | 4 +---
 Framework/API/test/MultiPeriodGroupAlgorithmTest.h         | 4 +---
 Framework/API/test/MultiPeriodGroupTestBase.h              | 4 +---
 Framework/API/test/MultiPeriodGroupWorkerTest.h            | 4 +---
 Framework/API/test/MultipleExperimentInfosTest.h           | 4 +---
 Framework/API/test/MultipleFilePropertyTest.h              | 4 +---
 Framework/API/test/NotebookBuilderTest.h                   | 4 +---
 Framework/API/test/NotebookWriterTest.h                    | 4 +---
 Framework/API/test/NumericAxisTest.h                       | 4 +---
 Framework/API/test/NumericAxisValidatorTest.h              | 4 +---
 Framework/API/test/OrientedLatticeValidatorTest.h          | 4 +---
 Framework/API/test/ParamFunctionAttributeHolderTest.h      | 4 +---
 Framework/API/test/ParameterReferenceTest.h                | 4 +---
 Framework/API/test/ParameterTieTest.h                      | 4 +---
 Framework/API/test/PeakFunctionIntegratorTest.h            | 4 +---
 Framework/API/test/PrecompiledHeader.h                     | 4 +---
 Framework/API/test/ProgressTest.h                          | 4 +---
 Framework/API/test/ProjectionTest.h                        | 4 +---
 Framework/API/test/PropertyManagerHelper.h                 | 4 +---
 Framework/API/test/RawCountValidatorTest.h                 | 4 +---
 Framework/API/test/RemoteJobManagerFactoryTest.h           | 4 +---
 Framework/API/test/ResizeRectangularDetectorHelperTest.h   | 4 +---
 Framework/API/test/RunTest.h                               | 4 +---
 Framework/API/test/SampleShapeValidatorTest.h              | 4 +---
 Framework/API/test/SampleTest.h                            | 4 +---
 Framework/API/test/SampleValidatorTest.h                   | 4 +---
 Framework/API/test/ScopedWorkspaceTest.h                   | 4 +---
 Framework/API/test/ScriptBuilderTest.h                     | 4 +---
 Framework/API/test/SingleCountValidatorTest.h              | 4 +---
 Framework/API/test/SpectraAxisTest.h                       | 4 +---
 Framework/API/test/SpectraAxisValidatorTest.h              | 4 +---
 Framework/API/test/SpectrumDetectorMappingTest.h           | 4 +---
 Framework/API/test/SpectrumInfoTest.h                      | 4 +---
 Framework/API/test/TempFunctionTest.h                      | 4 +---
 Framework/API/test/TextAxisTest.h                          | 4 +---
 Framework/API/test/TransformScaleFactoryTest.h             | 4 +---
 Framework/API/test/VectorParameterParserTest.h             | 4 +---
 Framework/API/test/VectorParameterTest.h                   | 4 +---
 Framework/API/test/WorkspaceFactoryTest.h                  | 4 +---
 Framework/API/test/WorkspaceGroupTest.h                    | 4 +---
 Framework/API/test/WorkspaceHasDxValidatorTest.h           | 4 +---
 Framework/API/test/WorkspaceHistoryIOTest.h                | 4 +---
 Framework/API/test/WorkspaceHistoryTest.h                  | 4 +---
 Framework/API/test/WorkspaceNearestNeighbourInfoTest.h     | 4 +---
 Framework/API/test/WorkspaceNearestNeighboursTest.h        | 4 +---
 Framework/API/test/WorkspaceOpOverloadsTest.h              | 4 +---
 Framework/API/test/WorkspacePropertyTest.h                 | 4 +---
 Framework/API/test/WorkspaceUnitValidatorTest.h            | 4 +---
 319 files changed, 322 insertions(+), 984 deletions(-)

diff --git a/Framework/API/inc/MantidAPI/ADSValidator.h b/Framework/API/inc/MantidAPI/ADSValidator.h
index 5efc517329b..b43de86d127 100644
--- a/Framework/API/inc/MantidAPI/ADSValidator.h
+++ b/Framework/API/inc/MantidAPI/ADSValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ADSVALIDATOR_H_
-#define MANTID_API_ADSVALIDATOR_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -59,4 +58,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_ADSVALIDATOR_H_ */
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/AlgoTimeRegister.h b/Framework/API/inc/MantidAPI/AlgoTimeRegister.h
index 3f5c1cb7fe1..f9b8a61b2a3 100644
--- a/Framework/API/inc/MantidAPI/AlgoTimeRegister.h
+++ b/Framework/API/inc/MantidAPI/AlgoTimeRegister.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGOTIMEREGISTER_H_
-#define MANTID_API_ALGOTIMEREGISTER_H_
+#pragma once
 
 #include <mutex>
 #include <thread>
@@ -59,4 +58,3 @@ private:
 } // namespace Instrumentation
 } // namespace Mantid
 
-#endif /* MANTID_API_ALGOTIMEREGISTER_H_ */
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/Algorithm.h b/Framework/API/inc/MantidAPI/Algorithm.h
index c3b3ced81de..17d4d845118 100644
--- a/Framework/API/inc/MantidAPI/Algorithm.h
+++ b/Framework/API/inc/MantidAPI/Algorithm.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHM_H_
-#define MANTID_API_ALGORITHM_H_
+#pragma once
 
 #include <atomic>
 
@@ -522,4 +521,3 @@ using Algorithm_sptr = boost::shared_ptr<Algorithm>;
       (Mantid::API::AlgorithmFactory::Instance().subscribe<classname>()), 0)); \
   }
 
-#endif /*MANTID_API_ALGORITHM_H_*/
diff --git a/Framework/API/inc/MantidAPI/AlgorithmFactory.h b/Framework/API/inc/MantidAPI/AlgorithmFactory.h
index 0ad9508293e..6acaecb0133 100644
--- a/Framework/API/inc/MantidAPI/AlgorithmFactory.h
+++ b/Framework/API/inc/MantidAPI/AlgorithmFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHMFACTORY_H_
-#define MANTID_API_ALGORITHMFACTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -171,4 +170,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /*MANTID_API_ALGORITHMFACTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/AlgorithmFactoryObserver.h b/Framework/API/inc/MantidAPI/AlgorithmFactoryObserver.h
index 29329b35c6e..0e30e1a3f0e 100644
--- a/Framework/API/inc/MantidAPI/AlgorithmFactoryObserver.h
+++ b/Framework/API/inc/MantidAPI/AlgorithmFactoryObserver.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_KERNEL_ALGORITHMFACTORYOBSERVER_H_
-#define MANTID_KERNEL_ALGORITHMFACTORYOBSERVER_H_
+#pragma once
 
 #include "MantidAPI/AlgorithmFactory.h"
 #include <Poco/NObserver.h>
@@ -53,4 +52,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_KERNEL_ALGORITHMFACTORYOBSERVER_H_*/
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/AlgorithmHasProperty.h b/Framework/API/inc/MantidAPI/AlgorithmHasProperty.h
index 44b6661db2e..c786842d2f0 100644
--- a/Framework/API/inc/MantidAPI/AlgorithmHasProperty.h
+++ b/Framework/API/inc/MantidAPI/AlgorithmHasProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHMHASPROPERTY_H_
-#define MANTID_API_ALGORITHMHASPROPERTY_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidKernel/TypedValidator.h"
@@ -41,4 +40,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_ALGORITHMHASPROPERTY_H_ */
diff --git a/Framework/API/inc/MantidAPI/AlgorithmHistory.h b/Framework/API/inc/MantidAPI/AlgorithmHistory.h
index 59f63f11121..1cf5325acc5 100644
--- a/Framework/API/inc/MantidAPI/AlgorithmHistory.h
+++ b/Framework/API/inc/MantidAPI/AlgorithmHistory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHMHISTORY_H_
-#define MANTID_API_ALGORITHMHISTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -152,4 +151,3 @@ MANTID_API_DLL std::ostream &operator<<(std::ostream &,
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_ALGORITHMHISTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/AlgorithmManager.h b/Framework/API/inc/MantidAPI/AlgorithmManager.h
index eb892ae5f1e..a6fc251068d 100644
--- a/Framework/API/inc/MantidAPI/AlgorithmManager.h
+++ b/Framework/API/inc/MantidAPI/AlgorithmManager.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHMMANAGER_H_
-#define MANTID_API_ALGORITHMMANAGER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -101,4 +100,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /* MANTID_API_ALGORITHMMANAGER_H_ */
diff --git a/Framework/API/inc/MantidAPI/AlgorithmObserver.h b/Framework/API/inc/MantidAPI/AlgorithmObserver.h
index aef65abb86b..c3a9c829b54 100644
--- a/Framework/API/inc/MantidAPI/AlgorithmObserver.h
+++ b/Framework/API/inc/MantidAPI/AlgorithmObserver.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHMOBSERVER_H_
-#define MANTID_API_ALGORITHMOBSERVER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -76,4 +75,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_ALGORITHMOBSERVER_H_*/
diff --git a/Framework/API/inc/MantidAPI/AlgorithmProperty.h b/Framework/API/inc/MantidAPI/AlgorithmProperty.h
index 6f3c8db8a09..90b4f956e0a 100644
--- a/Framework/API/inc/MantidAPI/AlgorithmProperty.h
+++ b/Framework/API/inc/MantidAPI/AlgorithmProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHMPROPERTY_H_
-#define MANTID_API_ALGORITHMPROPERTY_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidKernel/NullValidator.h"
@@ -85,5 +84,3 @@ private:
 
 } // namespace API
 } // namespace Mantid
-
-#endif /* MANTID_API_ALGORITHMPROPERTY_H_ */
diff --git a/Framework/API/inc/MantidAPI/AlgorithmProxy.h b/Framework/API/inc/MantidAPI/AlgorithmProxy.h
index f756ba65064..e3dceacb090 100644
--- a/Framework/API/inc/MantidAPI/AlgorithmProxy.h
+++ b/Framework/API/inc/MantidAPI/AlgorithmProxy.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHMPROXY_H_
-#define MANTID_API_ALGORITHMPROXY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -198,5 +197,3 @@ private:
 
 } // namespace API
 } // namespace Mantid
-
-#endif /*MANTID_API_ALGORITHMPROXY_H_*/
diff --git a/Framework/API/inc/MantidAPI/AnalysisDataService.h b/Framework/API/inc/MantidAPI/AnalysisDataService.h
index 126554a263e..6df456a7844 100644
--- a/Framework/API/inc/MantidAPI/AnalysisDataService.h
+++ b/Framework/API/inc/MantidAPI/AnalysisDataService.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_KERNEL_ANALYSISDATASERVICE_H_
-#define MANTID_KERNEL_ANALYSISDATASERVICE_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -231,4 +230,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /*MANTID_KERNEL_ANALYSISDATASERVICE_H_*/
diff --git a/Framework/API/inc/MantidAPI/AnalysisDataServiceObserver.h b/Framework/API/inc/MantidAPI/AnalysisDataServiceObserver.h
index 3445102cf04..b7a05187b27 100644
--- a/Framework/API/inc/MantidAPI/AnalysisDataServiceObserver.h
+++ b/Framework/API/inc/MantidAPI/AnalysisDataServiceObserver.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_KERNEL_ANALYSISDATASERVICEOBSERVER_H_
-#define MANTID_KERNEL_ANALYSISDATASERVICEOBSERVER_H_
+#pragma once
 
 #include "MantidAPI/AnalysisDataService.h"
 #include "MantidAPI/DllConfig.h"
@@ -137,4 +136,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_KERNEL_ANALYSISDATASERVICEOBSERVER_H_*/
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/ArchiveSearchFactory.h b/Framework/API/inc/MantidAPI/ArchiveSearchFactory.h
index d669139b0db..81d7cc6012c 100644
--- a/Framework/API/inc/MantidAPI/ArchiveSearchFactory.h
+++ b/Framework/API/inc/MantidAPI/ArchiveSearchFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ARCHIVESEARCHFACTORY_H_
-#define MANTID_API_ARCHIVESEARCHFACTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -53,4 +52,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif // MANTID_API_ARCHIVESEARCHFACTORY_H_
diff --git a/Framework/API/inc/MantidAPI/Axis.h b/Framework/API/inc/MantidAPI/Axis.h
index 4aeaf05bdea..e48fc3a7c1d 100644
--- a/Framework/API/inc/MantidAPI/Axis.h
+++ b/Framework/API/inc/MantidAPI/Axis.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_AXIS_H_
-#define MANTID_API_AXIS_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidGeometry/IDTypes.h"
@@ -105,4 +104,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_AXIS_H_*/
diff --git a/Framework/API/inc/MantidAPI/BinEdgeAxis.h b/Framework/API/inc/MantidAPI/BinEdgeAxis.h
index e9e7bf4d0bb..720a2825655 100644
--- a/Framework/API/inc/MantidAPI/BinEdgeAxis.h
+++ b/Framework/API/inc/MantidAPI/BinEdgeAxis.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_BINEDGEAXIS_H_
-#define MANTID_API_BINEDGEAXIS_H_
+#pragma once
 
 #include "MantidAPI/NumericAxis.h"
 
@@ -39,4 +38,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_BINEDGEAXIS_H_ */
diff --git a/Framework/API/inc/MantidAPI/BoostOptionalToAlgorithmProperty.h b/Framework/API/inc/MantidAPI/BoostOptionalToAlgorithmProperty.h
index fd6bd104d33..f304cf659db 100644
--- a/Framework/API/inc/MantidAPI/BoostOptionalToAlgorithmProperty.h
+++ b/Framework/API/inc/MantidAPI/BoostOptionalToAlgorithmProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_BOOSTOPTIONALTOALGORITHMPROPERTY_H_
-#define MANTID_API_BOOSTOPTIONALTOALGORITHMPROPERTY_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/DllConfig.h"
@@ -101,4 +100,3 @@ DLLExport boost::optional<std::string> checkForOptionalInstrumentDefault(
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_BOOSTOPTIONALTOALGORITHMPROPERTY_H_
diff --git a/Framework/API/inc/MantidAPI/BoxController.h b/Framework/API/inc/MantidAPI/BoxController.h
index 897f95d2dca..6bb93387760 100644
--- a/Framework/API/inc/MantidAPI/BoxController.h
+++ b/Framework/API/inc/MantidAPI/BoxController.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef BOXCONTROLLER_H_
-#define BOXCONTROLLER_H_
+#pragma once
 
 #include "MantidAPI/IBoxControllerIO.h"
 #include "MantidKernel/DiskBuffer.h"
@@ -547,4 +546,3 @@ using BoxController_const_sptr = boost::shared_ptr<const BoxController>;
 
 } // namespace Mantid
 
-#endif /* SPLITCONTROLLER_H_ */
diff --git a/Framework/API/inc/MantidAPI/CatalogFactory.h b/Framework/API/inc/MantidAPI/CatalogFactory.h
index 6fed74f3a2f..228fdb85349 100644
--- a/Framework/API/inc/MantidAPI/CatalogFactory.h
+++ b/Framework/API/inc/MantidAPI/CatalogFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_CATALOGFACTORYIMPL_H_
-#define MANTID_API_CATALOGFACTORYIMPL_H_
+#pragma once
 
 /* Used to register Catalog classes into the factory. creates a global object in
  *an
@@ -76,4 +75,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /*MANTID_API_CATALOGFACTORYIMPL_H_*/
diff --git a/Framework/API/inc/MantidAPI/CatalogManager.h b/Framework/API/inc/MantidAPI/CatalogManager.h
index a228fdfb533..7c3ac54df97 100644
--- a/Framework/API/inc/MantidAPI/CatalogManager.h
+++ b/Framework/API/inc/MantidAPI/CatalogManager.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_ICAT_CATALOGMANAGERIMPL_H_
-#define MANTID_ICAT_CATALOGMANAGERIMPL_H_
+#pragma once
 
 #include "MantidAPI/ICatalog.h"
 #include "MantidKernel/SingletonHolder.h"
@@ -63,4 +62,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
     Kernel::SingletonHolder<Mantid::API::CatalogManagerImpl>;
 }
 } // namespace Mantid
-#endif /* MANTID_ICAT_CATALOGMANAGERIMPL_H_ */
diff --git a/Framework/API/inc/MantidAPI/CatalogSession.h b/Framework/API/inc/MantidAPI/CatalogSession.h
index 22dd3290ff1..3769b48cc20 100644
--- a/Framework/API/inc/MantidAPI/CatalogSession.h
+++ b/Framework/API/inc/MantidAPI/CatalogSession.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_CATALOGSESSION_H_
-#define MANTID_API_CATALOGSESSION_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "boost/shared_ptr.hpp"
@@ -40,4 +39,3 @@ using CatalogSession_const_sptr = boost::shared_ptr<const CatalogSession>;
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_CATALOGSESSION_H_ */
diff --git a/Framework/API/inc/MantidAPI/Citation.h b/Framework/API/inc/MantidAPI/Citation.h
index 24adcd50992..8cec497d9a9 100644
--- a/Framework/API/inc/MantidAPI/Citation.h
+++ b/Framework/API/inc/MantidAPI/Citation.h
@@ -5,8 +5,7 @@
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
 
-#ifndef MANTID_API_CITATION_CITATION_H_
-#define MANTID_API_CITATION_CITATION_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 
@@ -74,4 +73,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_CITATION_CITATION_H_ */
diff --git a/Framework/API/inc/MantidAPI/Column.h b/Framework/API/inc/MantidAPI/Column.h
index 38c7518da2c..d68488c46f3 100644
--- a/Framework/API/inc/MantidAPI/Column.h
+++ b/Framework/API/inc/MantidAPI/Column.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ICOLUMN_H_
-#define MANTID_API_ICOLUMN_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -238,4 +237,3 @@ using Column_const_sptr = boost::shared_ptr<const Column>;
 
 } // namespace API
 } // Namespace Mantid
-#endif /*MANTID_API_ICOLUMN_H_*/
diff --git a/Framework/API/inc/MantidAPI/ColumnFactory.h b/Framework/API/inc/MantidAPI/ColumnFactory.h
index ece4590f057..34d77526b92 100644
--- a/Framework/API/inc/MantidAPI/ColumnFactory.h
+++ b/Framework/API/inc/MantidAPI/ColumnFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_COLUMNFACTORY_H_
-#define MANTID_API_COLUMNFACTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -61,4 +60,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /*MANTID_API_COLUMNFACTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/CommonBinsValidator.h b/Framework/API/inc/MantidAPI/CommonBinsValidator.h
index 8f5197b033c..6a3fc1177a4 100644
--- a/Framework/API/inc/MantidAPI/CommonBinsValidator.h
+++ b/Framework/API/inc/MantidAPI/CommonBinsValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_COMMONBINSVALIDATOR_H_
-#define MANTID_API_COMMONBINSVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceValidator.h"
 
@@ -34,4 +33,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_COMMONBINSVALIDATOR_H_ */
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/CompositeCatalog.h b/Framework/API/inc/MantidAPI/CompositeCatalog.h
index 749af14b134..2fa199ba69b 100644
--- a/Framework/API/inc/MantidAPI/CompositeCatalog.h
+++ b/Framework/API/inc/MantidAPI/CompositeCatalog.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_ICAT_COMPOSITECATALOG_H_
-#define MANTID_ICAT_COMPOSITECATALOG_H_
+#pragma once
 
 #include "MantidAPI/ICatalog.h"
 
@@ -61,4 +60,3 @@ private:
 };
 } // namespace API
 } // namespace Mantid
-#endif /* MANTID_ICAT_COMPOSITECATALOG_H_ */
diff --git a/Framework/API/inc/MantidAPI/CompositeDomain.h b/Framework/API/inc/MantidAPI/CompositeDomain.h
index 5f98620438b..e85f12634f1 100644
--- a/Framework/API/inc/MantidAPI/CompositeDomain.h
+++ b/Framework/API/inc/MantidAPI/CompositeDomain.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_COMPOSITEDOMAIN_H_
-#define MANTID_API_COMPOSITEDOMAIN_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -34,4 +33,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_COMPOSITEDOMAIN_H_*/
diff --git a/Framework/API/inc/MantidAPI/CompositeDomainMD.h b/Framework/API/inc/MantidAPI/CompositeDomainMD.h
index 35bc9e4a08d..54cfaa578d7 100644
--- a/Framework/API/inc/MantidAPI/CompositeDomainMD.h
+++ b/Framework/API/inc/MantidAPI/CompositeDomainMD.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_COMPOSITEDOMAINMD_H_
-#define MANTID_API_COMPOSITEDOMAINMD_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -47,4 +46,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_COMPOSITEDOMAINMD_H_*/
diff --git a/Framework/API/inc/MantidAPI/CompositeFunction.h b/Framework/API/inc/MantidAPI/CompositeFunction.h
index dc7b471752b..457462de034 100644
--- a/Framework/API/inc/MantidAPI/CompositeFunction.h
+++ b/Framework/API/inc/MantidAPI/CompositeFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_COMPOSITEFUNCTION_H_
-#define MANTID_API_COMPOSITEFUNCTION_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -295,4 +294,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_COMPOSITEFUNCTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/ConstraintFactory.h b/Framework/API/inc/MantidAPI/ConstraintFactory.h
index 80d1e11a4d5..1b6c641f238 100644
--- a/Framework/API/inc/MantidAPI/ConstraintFactory.h
+++ b/Framework/API/inc/MantidAPI/ConstraintFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_CONSTRAINTFACTORY_H_
-#define MANTID_API_CONSTRAINTFACTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -83,4 +82,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
        0));                                                                    \
   }
 
-#endif /*MANTID_API_CONSTRAINTFACTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/CoordTransform.h b/Framework/API/inc/MantidAPI/CoordTransform.h
index 1018db380b4..f34ea0f7987 100644
--- a/Framework/API/inc/MantidAPI/CoordTransform.h
+++ b/Framework/API/inc/MantidAPI/CoordTransform.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_MDEVENTS_COORDTRANSFORM_H_
-#define MANTID_MDEVENTS_COORDTRANSFORM_H_
+#pragma once
 
 #include "MantidAPI/SingleValueParameter.h"
 #include "MantidGeometry/MDGeometry/IMDDimension.h"
@@ -73,4 +72,3 @@ using CoordTransform_const_sptr = boost::shared_ptr<const CoordTransform>;
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_MDEVENTS_COORDTRANSFORM_H_ */
diff --git a/Framework/API/inc/MantidAPI/CostFunctionFactory.h b/Framework/API/inc/MantidAPI/CostFunctionFactory.h
index ca70621a7d5..60d3ffb5cb3 100644
--- a/Framework/API/inc/MantidAPI/CostFunctionFactory.h
+++ b/Framework/API/inc/MantidAPI/CostFunctionFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_COSTFUNCTIONFACTORY_H_
-#define MANTID_API_COSTFUNCTIONFACTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -62,4 +61,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /*MANTID_API_COSTFUNCTIONFACTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/DataProcessorAlgorithm.h b/Framework/API/inc/MantidAPI/DataProcessorAlgorithm.h
index 6a044b6b121..80d537c7610 100644
--- a/Framework/API/inc/MantidAPI/DataProcessorAlgorithm.h
+++ b/Framework/API/inc/MantidAPI/DataProcessorAlgorithm.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_DATAPROCESSORALGORITHM_H_
-#define MANTID_API_DATAPROCESSORALGORITHM_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/AlgorithmManager.h"
@@ -152,4 +151,3 @@ using DistributedDataProcessorAlgorithm =
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_DATAPROCESSORALGORITHM_H_ */
diff --git a/Framework/API/inc/MantidAPI/DeclareUserAlg.h b/Framework/API/inc/MantidAPI/DeclareUserAlg.h
index b811a4196e0..f5822bb9239 100644
--- a/Framework/API/inc/MantidAPI/DeclareUserAlg.h
+++ b/Framework/API/inc/MantidAPI/DeclareUserAlg.h
@@ -4,12 +4,10 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef DECLAREUSERALG_H_
-#define DECLAREUSERALG_H_
+#pragma once
 
 #define DECLARE_USER_ALG(x)                                                    \
   Algorithm *x##_create() { return new x; }                                    \
                                                                                \
   void x##_destroy(Algorithm *p) { delete p; }
 
-#endif /*DECLAREUSERALG_H_*/
diff --git a/Framework/API/inc/MantidAPI/DeprecatedAlgorithm.h b/Framework/API/inc/MantidAPI/DeprecatedAlgorithm.h
index eb11179b740..7cce8b71e51 100644
--- a/Framework/API/inc/MantidAPI/DeprecatedAlgorithm.h
+++ b/Framework/API/inc/MantidAPI/DeprecatedAlgorithm.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef DEPRECATEDALGORITHM_H_
-#define DEPRECATEDALGORITHM_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/DllConfig.h"
@@ -43,4 +42,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* DEPRECATEDALGORITHM_H_ */
diff --git a/Framework/API/inc/MantidAPI/DetectorSearcher.h b/Framework/API/inc/MantidAPI/DetectorSearcher.h
index 7bde1a227ad..e4b1e6449d8 100644
--- a/Framework/API/inc/MantidAPI/DetectorSearcher.h
+++ b/Framework/API/inc/MantidAPI/DetectorSearcher.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_DETECTOR_SEARCHER_H_
-#define MANTID_DETECTOR_SEARCHER_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidGeometry/Instrument.h"
@@ -89,4 +88,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif
diff --git a/Framework/API/inc/MantidAPI/DistributedAlgorithm.h b/Framework/API/inc/MantidAPI/DistributedAlgorithm.h
index 12c6e308c33..7482336ccc0 100644
--- a/Framework/API/inc/MantidAPI/DistributedAlgorithm.h
+++ b/Framework/API/inc/MantidAPI/DistributedAlgorithm.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_DISTRIBUTEDALGORITHM_H_
-#define MANTID_API_DISTRIBUTEDALGORITHM_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/DllConfig.h"
@@ -45,4 +44,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_DISTRIBUTEDALGORITHM_H_ */
diff --git a/Framework/API/inc/MantidAPI/DllConfig.h b/Framework/API/inc/MantidAPI/DllConfig.h
index 846a9da71ae..4ae1c17ebcb 100644
--- a/Framework/API/inc/MantidAPI/DllConfig.h
+++ b/Framework/API/inc/MantidAPI/DllConfig.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_DLLCONFIG_H_
-#define MANTID_API_DLLCONFIG_H_
+#pragma once
 
 /*
     This file contains the DLLExport/DLLImport linkage configuration for the
@@ -22,5 +21,3 @@
 #define MANTID_API_DLL DLLImport
 #define EXTERN_MANTID_API EXTERN_IMPORT
 #endif /* IN_MANTID_API*/
-
-#endif // MANTID_API_DLLCONFIG_H_
diff --git a/Framework/API/inc/MantidAPI/DomainCreatorFactory.h b/Framework/API/inc/MantidAPI/DomainCreatorFactory.h
index 3d8fe47ccf9..115ec5d2675 100644
--- a/Framework/API/inc/MantidAPI/DomainCreatorFactory.h
+++ b/Framework/API/inc/MantidAPI/DomainCreatorFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_DOMAINCREATORFACTORY_H_
-#define MANTID_API_DOMAINCREATORFACTORY_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidKernel/DynamicFactory.h"
@@ -71,4 +70,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /* MANTID_API_DOMAINCREATORFACTORY_H_ */
diff --git a/Framework/API/inc/MantidAPI/EnabledWhenWorkspaceIsType.h b/Framework/API/inc/MantidAPI/EnabledWhenWorkspaceIsType.h
index 8c908f65b6d..d29c63705b9 100644
--- a/Framework/API/inc/MantidAPI/EnabledWhenWorkspaceIsType.h
+++ b/Framework/API/inc/MantidAPI/EnabledWhenWorkspaceIsType.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ENABLEDWHENWORKSPACEISTYPE_H_
-#define MANTID_API_ENABLEDWHENWORKSPACEISTYPE_H_
+#pragma once
 
 #include "MantidAPI/AnalysisDataService.h"
 #include "MantidAPI/Workspace_fwd.h"
@@ -106,4 +105,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_ENABLEDWHENWORKSPACEISTYPE_H_ */
diff --git a/Framework/API/inc/MantidAPI/EqualBinSizesValidator.h b/Framework/API/inc/MantidAPI/EqualBinSizesValidator.h
index 28b5993ce7b..b22d22698b0 100644
--- a/Framework/API/inc/MantidAPI/EqualBinSizesValidator.h
+++ b/Framework/API/inc/MantidAPI/EqualBinSizesValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_EQUALBINSIZESVALIDATOR_H_
-#define MANTID_API_EQUALBINSIZESVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/MatrixWorkspaceValidator.h"
@@ -38,4 +37,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_EQUALBINSIZESVALIDATOR_H_ */
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/ExperimentInfo.h b/Framework/API/inc/MantidAPI/ExperimentInfo.h
index 52dfcdc1816..c1ae94db189 100644
--- a/Framework/API/inc/MantidAPI/ExperimentInfo.h
+++ b/Framework/API/inc/MantidAPI/ExperimentInfo.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_EXPERIMENTINFO_H_
-#define MANTID_API_EXPERIMENTINFO_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 
@@ -236,4 +235,3 @@ using ExperimentInfo_const_sptr = boost::shared_ptr<const ExperimentInfo>;
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_EXPERIMENTINFO_H_ */
diff --git a/Framework/API/inc/MantidAPI/Expression.h b/Framework/API/inc/MantidAPI/Expression.h
index 0c80a0368cd..e0fd77d50e9 100644
--- a/Framework/API/inc/MantidAPI/Expression.h
+++ b/Framework/API/inc/MantidAPI/Expression.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_EXPRESSION_H
-#define MANTID_API_EXPRESSION_H
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 
@@ -221,5 +220,3 @@ private:
 
 } // namespace API
 } // namespace Mantid
-
-#endif /* EXPRESSION_H */
diff --git a/Framework/API/inc/MantidAPI/FileBackedExperimentInfo.h b/Framework/API/inc/MantidAPI/FileBackedExperimentInfo.h
index 9d17aad67cc..1943c80087d 100644
--- a/Framework/API/inc/MantidAPI/FileBackedExperimentInfo.h
+++ b/Framework/API/inc/MantidAPI/FileBackedExperimentInfo.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FILEBACKEDEXPERIMENTINFO_H_
-#define MANTID_API_FILEBACKEDEXPERIMENTINFO_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/ExperimentInfo.h"
@@ -35,4 +34,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_FILEBACKEDEXPERIMENTINFO_H_ */
diff --git a/Framework/API/inc/MantidAPI/FileFinder.h b/Framework/API/inc/MantidAPI/FileFinder.h
index 5ce8f4be1c9..3ce16b61cff 100644
--- a/Framework/API/inc/MantidAPI/FileFinder.h
+++ b/Framework/API/inc/MantidAPI/FileFinder.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FILEFINDER_H_
-#define MANTID_API_FILEFINDER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -95,4 +94,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif // MANTID_API_FILEFINDER_H_
diff --git a/Framework/API/inc/MantidAPI/FileLoaderRegistry.h b/Framework/API/inc/MantidAPI/FileLoaderRegistry.h
index 5404841ae5d..ea608352ca2 100644
--- a/Framework/API/inc/MantidAPI/FileLoaderRegistry.h
+++ b/Framework/API/inc/MantidAPI/FileLoaderRegistry.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FILELOADERREGISTRY_H_
-#define MANTID_API_FILELOADERREGISTRY_H_
+#pragma once
 
 #include "MantidAPI/AlgorithmFactory.h"
 #include "MantidAPI/IFileLoader.h"
@@ -143,5 +142,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
     Mantid::Kernel::SingletonHolder<Mantid::API::FileLoaderRegistryImpl>;
 }
 } // namespace Mantid
-
-#endif /* MANTID_API_FILELOADERREGISTRY_H_ */
diff --git a/Framework/API/inc/MantidAPI/FileProperty.h b/Framework/API/inc/MantidAPI/FileProperty.h
index 9edf4ca07d9..4d7a8463016 100644
--- a/Framework/API/inc/MantidAPI/FileProperty.h
+++ b/Framework/API/inc/MantidAPI/FileProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FILEPROPERTY_H_
-#define MANTID_API_FILEPROPERTY_H_
+#pragma once
 
 //-----------------------------------------------------------------
 // Includes
@@ -128,5 +127,3 @@ private:
 #endif
 } // namespace API
 } // namespace Mantid
-
-#endif // MANTID_API_FILEPROPERTY_H_
diff --git a/Framework/API/inc/MantidAPI/FrameworkManager.h b/Framework/API/inc/MantidAPI/FrameworkManager.h
index f0a785b7cbf..b5a43d33e7b 100644
--- a/Framework/API/inc/MantidAPI/FrameworkManager.h
+++ b/Framework/API/inc/MantidAPI/FrameworkManager.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FRAMEWORKMANAGER_H_
-#define MANTID_API_FRAMEWORKMANAGER_H_
+#pragma once
 
 #include <string>
 
@@ -131,5 +130,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
     Mantid::Kernel::SingletonHolder<Mantid::API::FrameworkManagerImpl>;
 }
 } // namespace Mantid
-
-#endif /*MANTID_API_FRAMEWORKMANAGER_H_*/
diff --git a/Framework/API/inc/MantidAPI/FuncMinimizerFactory.h b/Framework/API/inc/MantidAPI/FuncMinimizerFactory.h
index afdd6900dbd..019b381ad01 100644
--- a/Framework/API/inc/MantidAPI/FuncMinimizerFactory.h
+++ b/Framework/API/inc/MantidAPI/FuncMinimizerFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCMINIMIZERFACTORY_H_
-#define MANTID_API_FUNCMINIMIZERFACTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -72,4 +71,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
        0));                                                                    \
   }
 
-#endif /*MANTID_API_FUNCMINIMIZERFACTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/FunctionDomain.h b/Framework/API/inc/MantidAPI/FunctionDomain.h
index 6e6d61032a0..b843bd4e1a9 100644
--- a/Framework/API/inc/MantidAPI/FunctionDomain.h
+++ b/Framework/API/inc/MantidAPI/FunctionDomain.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCTIONDOMAIN_H_
-#define MANTID_API_FUNCTIONDOMAIN_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -45,5 +44,3 @@ using FunctionDomain_sptr = boost::shared_ptr<FunctionDomain>;
 
 } // namespace API
 } // namespace Mantid
-
-#endif /*MANTID_API_FUNCTIONDOMAIN_H_*/
diff --git a/Framework/API/inc/MantidAPI/FunctionDomain1D.h b/Framework/API/inc/MantidAPI/FunctionDomain1D.h
index 297c1afa23e..5438a788998 100644
--- a/Framework/API/inc/MantidAPI/FunctionDomain1D.h
+++ b/Framework/API/inc/MantidAPI/FunctionDomain1D.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCTIONDOMAIN1D_H_
-#define MANTID_API_FUNCTIONDOMAIN1D_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -165,4 +164,3 @@ using FunctionDomain1D_const_sptr = boost::shared_ptr<const FunctionDomain1D>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_FUNCTIONDOMAIN1D_H_*/
diff --git a/Framework/API/inc/MantidAPI/FunctionDomainGeneral.h b/Framework/API/inc/MantidAPI/FunctionDomainGeneral.h
index 9ab60e93c4f..63075e32890 100644
--- a/Framework/API/inc/MantidAPI/FunctionDomainGeneral.h
+++ b/Framework/API/inc/MantidAPI/FunctionDomainGeneral.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCTIONDOMAINGENERAL_H_
-#define MANTID_API_FUNCTIONDOMAINGENERAL_H_
+#pragma once
 
 #include "MantidAPI/FunctionDomain.h"
 #include <boost/shared_ptr.hpp>
@@ -38,4 +37,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_FUNCTIONDOMAINGENERAL_H_*/
diff --git a/Framework/API/inc/MantidAPI/FunctionDomainMD.h b/Framework/API/inc/MantidAPI/FunctionDomainMD.h
index 49650a0aa4d..5b0e826dd48 100644
--- a/Framework/API/inc/MantidAPI/FunctionDomainMD.h
+++ b/Framework/API/inc/MantidAPI/FunctionDomainMD.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCTIONDOMAINMD_H_
-#define MANTID_API_FUNCTIONDOMAINMD_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -56,4 +55,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_FUNCTIONDOMAINMD_H_*/
diff --git a/Framework/API/inc/MantidAPI/FunctionFactory.h b/Framework/API/inc/MantidAPI/FunctionFactory.h
index 33ae48456dc..e8674d71a97 100644
--- a/Framework/API/inc/MantidAPI/FunctionFactory.h
+++ b/Framework/API/inc/MantidAPI/FunctionFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCTIONFACTORY_H_
-#define MANTID_API_FUNCTIONFACTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -164,4 +163,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
                                      0));                                      \
   }
 
-#endif /*MANTID_API_FUNCTIONFACTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/FunctionGenerator.h b/Framework/API/inc/MantidAPI/FunctionGenerator.h
index f5fde4142a0..a73ca5d58fa 100644
--- a/Framework/API/inc/MantidAPI/FunctionGenerator.h
+++ b/Framework/API/inc/MantidAPI/FunctionGenerator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCTIONGENERATOR_H_
-#define MANTID_API_FUNCTIONGENERATOR_H_
+#pragma once
 
 #include "MantidAPI/IFunction.h"
 
@@ -135,4 +134,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_FUNCTIONGENERATOR_H_*/
diff --git a/Framework/API/inc/MantidAPI/FunctionParameterDecorator.h b/Framework/API/inc/MantidAPI/FunctionParameterDecorator.h
index fafcd59a2d2..21410e59f65 100644
--- a/Framework/API/inc/MantidAPI/FunctionParameterDecorator.h
+++ b/Framework/API/inc/MantidAPI/FunctionParameterDecorator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCTIONPARAMETERDECORATOR_H_
-#define MANTID_API_FUNCTIONPARAMETERDECORATOR_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/IFunction.h"
@@ -142,4 +141,3 @@ using FunctionParameterDecorator_sptr =
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_FUNCTIONPARAMETERDECORATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/FunctionProperty.h b/Framework/API/inc/MantidAPI/FunctionProperty.h
index 9e3ddbe6f31..ad3d09615c0 100644
--- a/Framework/API/inc/MantidAPI/FunctionProperty.h
+++ b/Framework/API/inc/MantidAPI/FunctionProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCTIONPROPERTY_H_
-#define MANTID_API_FUNCTIONPROPERTY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -85,4 +84,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_FUNCTIONPROPERTY_H_*/
diff --git a/Framework/API/inc/MantidAPI/FunctionValues.h b/Framework/API/inc/MantidAPI/FunctionValues.h
index 6b84d72c48a..4979b886ab7 100644
--- a/Framework/API/inc/MantidAPI/FunctionValues.h
+++ b/Framework/API/inc/MantidAPI/FunctionValues.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FUNCTIONVALUES_H_
-#define MANTID_API_FUNCTIONVALUES_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -111,4 +110,3 @@ using FunctionValues_sptr = boost::shared_ptr<FunctionValues>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_FUNCTIONVALUES_H_*/
diff --git a/Framework/API/inc/MantidAPI/GridDomain.h b/Framework/API/inc/MantidAPI/GridDomain.h
index f480a205cb8..1a6f480ced6 100644
--- a/Framework/API/inc/MantidAPI/GridDomain.h
+++ b/Framework/API/inc/MantidAPI/GridDomain.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_GRIDDOMAIN_H_
-#define MANTID_API_GRIDDOMAIN_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -48,4 +47,3 @@ using GridDomain_sptr = boost::shared_ptr<GridDomain>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_GRIDDOMAIN_H_*/
diff --git a/Framework/API/inc/MantidAPI/GridDomain1D.h b/Framework/API/inc/MantidAPI/GridDomain1D.h
index e7b1f51126c..3b9cab82660 100644
--- a/Framework/API/inc/MantidAPI/GridDomain1D.h
+++ b/Framework/API/inc/MantidAPI/GridDomain1D.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_GRIDDOMAIN1D_H_
-#define MANTID_API_GRIDDOMAIN1D_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -48,4 +47,3 @@ using GridDomain1D_sptr = boost::shared_ptr<GridDomain1D>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_GRIDDOMAIN1D_H_*/
diff --git a/Framework/API/inc/MantidAPI/GroupingLoader.h b/Framework/API/inc/MantidAPI/GroupingLoader.h
index 5f751d9700e..4df62f02f5f 100644
--- a/Framework/API/inc/MantidAPI/GroupingLoader.h
+++ b/Framework/API/inc/MantidAPI/GroupingLoader.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_GROUPINGLOADER_H_
-#define MANTID_API_GROUPINGLOADER_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/ITableWorkspace_fwd.h"
@@ -66,4 +65,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_GROUPINGLOADER_H_ */
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/HistoWorkspace.h b/Framework/API/inc/MantidAPI/HistoWorkspace.h
index 1f424adf34a..53f536bf243 100644
--- a/Framework/API/inc/MantidAPI/HistoWorkspace.h
+++ b/Framework/API/inc/MantidAPI/HistoWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_HISTOWORKSPACE_H_
-#define MANTID_API_HISTOWORKSPACE_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/MatrixWorkspace.h"
@@ -44,4 +43,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_HISTOWORKSPACE_H_ */
diff --git a/Framework/API/inc/MantidAPI/HistogramValidator.h b/Framework/API/inc/MantidAPI/HistogramValidator.h
index cc32b2302be..667c6b0a6af 100644
--- a/Framework/API/inc/MantidAPI/HistogramValidator.h
+++ b/Framework/API/inc/MantidAPI/HistogramValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_HISTOGRAMVALIDATOR_H_
-#define MANTID_API_HISTOGRAMVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceValidator.h"
 
@@ -37,4 +36,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_HISTOGRAMVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/HistoryItem.h b/Framework/API/inc/MantidAPI/HistoryItem.h
index b20bee12856..17573235d47 100644
--- a/Framework/API/inc/MantidAPI/HistoryItem.h
+++ b/Framework/API/inc/MantidAPI/HistoryItem.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_HISTORYITEM_H_
-#define MANTID_API_HISTORYITEM_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -46,4 +45,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_HISTORYITEM_H_*/
diff --git a/Framework/API/inc/MantidAPI/HistoryView.h b/Framework/API/inc/MantidAPI/HistoryView.h
index 49e508a80e3..8f41ac5961d 100644
--- a/Framework/API/inc/MantidAPI/HistoryView.h
+++ b/Framework/API/inc/MantidAPI/HistoryView.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_HISTORYVIEW_H_
-#define MANTID_API_HISTORYVIEW_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -65,4 +64,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_HISTORYVIEW_H_*/
diff --git a/Framework/API/inc/MantidAPI/IAlgorithm.h b/Framework/API/inc/MantidAPI/IAlgorithm.h
index 4df10263a59..b3b44aec107 100644
--- a/Framework/API/inc/MantidAPI/IAlgorithm.h
+++ b/Framework/API/inc/MantidAPI/IAlgorithm.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IALGORITHM_H_
-#define MANTID_API_IALGORITHM_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -178,4 +177,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_KERNEL_IALGORITHM_H_*/
diff --git a/Framework/API/inc/MantidAPI/IAlgorithm_fwd.h b/Framework/API/inc/MantidAPI/IAlgorithm_fwd.h
index 6359214884d..af8ece39dc0 100644
--- a/Framework/API/inc/MantidAPI/IAlgorithm_fwd.h
+++ b/Framework/API/inc/MantidAPI/IAlgorithm_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IALGORITHM_FWD_H_
-#define MANTID_API_IALGORITHM_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -30,4 +29,3 @@ using IAlgorithm_const_uptr = std::unique_ptr<const IAlgorithm>;
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_IALGORITHM_FWD_H_
diff --git a/Framework/API/inc/MantidAPI/IArchiveSearch.h b/Framework/API/inc/MantidAPI/IArchiveSearch.h
index 46b5840dbb7..a4f0a809e23 100644
--- a/Framework/API/inc/MantidAPI/IArchiveSearch.h
+++ b/Framework/API/inc/MantidAPI/IArchiveSearch.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IARCHIVESEARCH_H_
-#define MANTID_API_IARCHIVESEARCH_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -56,5 +55,3 @@ public:
 using IArchiveSearch_sptr = boost::shared_ptr<IArchiveSearch>;
 } // namespace API
 } // namespace Mantid
-
-#endif // MANTID_API_IARCHIVESEARCH_H_
diff --git a/Framework/API/inc/MantidAPI/IBackgroundFunction.h b/Framework/API/inc/MantidAPI/IBackgroundFunction.h
index b2033faffe8..93aa9fc8e00 100644
--- a/Framework/API/inc/MantidAPI/IBackgroundFunction.h
+++ b/Framework/API/inc/MantidAPI/IBackgroundFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IBACKGROUNDFUNCTION_H_
-#define MANTID_API_IBACKGROUNDFUNCTION_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -34,4 +33,3 @@ using IBackgroundFunction_sptr = boost::shared_ptr<IBackgroundFunction>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_IBACKGROUNDFUNCTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/IBoxControllerIO.h b/Framework/API/inc/MantidAPI/IBoxControllerIO.h
index 4bf2152b2c0..15f18add2bc 100644
--- a/Framework/API/inc/MantidAPI/IBoxControllerIO.h
+++ b/Framework/API/inc/MantidAPI/IBoxControllerIO.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef H_IBOXCONTROLLER_IO
-#define H_IBOXCONTROLLER_IO
+#pragma once
 #include "MantidKernel/DiskBuffer.h"
 #include "MantidKernel/System.h"
 
@@ -72,4 +71,3 @@ public:
 };
 } // namespace API
 } // namespace Mantid
-#endif
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/ICatalog.h b/Framework/API/inc/MantidAPI/ICatalog.h
index 290dae25fa0..7d39849bfaf 100644
--- a/Framework/API/inc/MantidAPI/ICatalog.h
+++ b/Framework/API/inc/MantidAPI/ICatalog.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ICATLOG_H_
-#define MANTID_API_ICATLOG_H_
+#pragma once
 
 #include "MantidAPI/CatalogSession.h"
 #include "MantidAPI/ITableWorkspace_fwd.h"
@@ -61,4 +60,3 @@ using ICatalog_const_sptr = boost::shared_ptr<const ICatalog>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_ICATLOG_H_*/
diff --git a/Framework/API/inc/MantidAPI/ICatalogInfoService.h b/Framework/API/inc/MantidAPI/ICatalogInfoService.h
index 9e58b9dd2fd..6ef7c455d76 100644
--- a/Framework/API/inc/MantidAPI/ICatalogInfoService.h
+++ b/Framework/API/inc/MantidAPI/ICatalogInfoService.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ICATLOGINFOSERVICE_H_
-#define MANTID_API_ICATLOGINFOSERVICE_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/ITableWorkspace_fwd.h"
@@ -43,4 +42,3 @@ using ICatalogInfoService_const_sptr =
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_ICATLOGINFOSERVICE_H_*/
diff --git a/Framework/API/inc/MantidAPI/IConstraint.h b/Framework/API/inc/MantidAPI/IConstraint.h
index 75070c3c010..3bee9174c63 100644
--- a/Framework/API/inc/MantidAPI/IConstraint.h
+++ b/Framework/API/inc/MantidAPI/IConstraint.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ICONSTRAINT_H_
-#define MANTID_API_ICONSTRAINT_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -73,4 +72,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_ICONSTRAINT_H_*/
diff --git a/Framework/API/inc/MantidAPI/ICostFunction.h b/Framework/API/inc/MantidAPI/ICostFunction.h
index 9e848f62c7d..f249ddac8cc 100644
--- a/Framework/API/inc/MantidAPI/ICostFunction.h
+++ b/Framework/API/inc/MantidAPI/ICostFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ICOSTFUNCTION_H_
-#define MANTID_API_ICOSTFUNCTION_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -75,4 +74,3 @@ using ICostFunction_sptr = boost::shared_ptr<ICostFunction>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_ICOSTFUNCTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/IDomainCreator.h b/Framework/API/inc/MantidAPI/IDomainCreator.h
index ed28e4f6ff9..35c72bad301 100644
--- a/Framework/API/inc/MantidAPI/IDomainCreator.h
+++ b/Framework/API/inc/MantidAPI/IDomainCreator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IDOMAINCREATOR_H_
-#define MANTID_API_IDOMAINCREATOR_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -151,4 +150,3 @@ using IDomainCreator_sptr = boost::shared_ptr<IDomainCreator>;
                                 0));                                           \
   }
 
-#endif /*MANTID_API_IDOMAINCREATOR_H_*/
diff --git a/Framework/API/inc/MantidAPI/IEventList.h b/Framework/API/inc/MantidAPI/IEventList.h
index 084b067e443..13758435d77 100644
--- a/Framework/API/inc/MantidAPI/IEventList.h
+++ b/Framework/API/inc/MantidAPI/IEventList.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IEVENTLIST_H_
-#define MANTID_API_IEVENTLIST_H_
+#pragma once
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/ISpectrum.h"
 #include "MantidAPI/MatrixWorkspace_fwd.h"
@@ -129,4 +128,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_IEVENTLIST_H_ */
diff --git a/Framework/API/inc/MantidAPI/IEventWorkspace.h b/Framework/API/inc/MantidAPI/IEventWorkspace.h
index b93b5de3aa9..fa75e6858b7 100644
--- a/Framework/API/inc/MantidAPI/IEventWorkspace.h
+++ b/Framework/API/inc/MantidAPI/IEventWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IEVENTWORKSPACE_H_
-#define MANTID_API_IEVENTWORKSPACE_H_
+#pragma once
 
 #include "MantidAPI/IEventList.h"
 #include "MantidAPI/IEventWorkspace_fwd.h"
@@ -71,4 +70,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_IEVENTWORKSPACE_H_
diff --git a/Framework/API/inc/MantidAPI/IEventWorkspace_fwd.h b/Framework/API/inc/MantidAPI/IEventWorkspace_fwd.h
index 737c0bdf063..23502039665 100644
--- a/Framework/API/inc/MantidAPI/IEventWorkspace_fwd.h
+++ b/Framework/API/inc/MantidAPI/IEventWorkspace_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IEVENTWORKSPACE_FWD_H_
-#define MANTID_API_IEVENTWORKSPACE_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -30,4 +29,3 @@ using IEventWorkspace_const_uptr = std::unique_ptr<const IEventWorkspace>;
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_IEVENTWORKSPACE_FWD_H_
diff --git a/Framework/API/inc/MantidAPI/IFileLoader.h b/Framework/API/inc/MantidAPI/IFileLoader.h
index 4d0caa463ab..01852339413 100644
--- a/Framework/API/inc/MantidAPI/IFileLoader.h
+++ b/Framework/API/inc/MantidAPI/IFileLoader.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFILELOADER_H_
-#define MANTID_API_IFILELOADER_H_
+#pragma once
 
 #include "MantidAPI/ParallelAlgorithm.h"
 #include "MantidKernel/FileDescriptor.h"
@@ -32,4 +31,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_IFILELOADER_H_ */
diff --git a/Framework/API/inc/MantidAPI/IFuncMinimizer.h b/Framework/API/inc/MantidAPI/IFuncMinimizer.h
index be301d13a9f..24c97b6cb78 100644
--- a/Framework/API/inc/MantidAPI/IFuncMinimizer.h
+++ b/Framework/API/inc/MantidAPI/IFuncMinimizer.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFUNCMINIMIZER_H_
-#define MANTID_API_IFUNCMINIMIZER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -64,4 +63,3 @@ using IFuncMinimizer_sptr = boost::shared_ptr<IFuncMinimizer>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_IFUNCMINIMIZER_H_*/
diff --git a/Framework/API/inc/MantidAPI/IFunction1D.h b/Framework/API/inc/MantidAPI/IFunction1D.h
index 44e95eeeb19..b980e4fa5ac 100644
--- a/Framework/API/inc/MantidAPI/IFunction1D.h
+++ b/Framework/API/inc/MantidAPI/IFunction1D.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFUNCTION1D_H_
-#define MANTID_API_IFUNCTION1D_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -92,4 +91,3 @@ using IFunction1D_sptr = boost::shared_ptr<IFunction1D>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_IFUNCTION1D_H_*/
diff --git a/Framework/API/inc/MantidAPI/IFunction1DSpectrum.h b/Framework/API/inc/MantidAPI/IFunction1DSpectrum.h
index 4f8452c8782..3fbd845bd9a 100644
--- a/Framework/API/inc/MantidAPI/IFunction1DSpectrum.h
+++ b/Framework/API/inc/MantidAPI/IFunction1DSpectrum.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFUNCTION1DSPECTRUM_H_
-#define MANTID_API_IFUNCTION1DSPECTRUM_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 
@@ -47,4 +46,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_IFUNCTION1DSPECTRUM_H_ */
diff --git a/Framework/API/inc/MantidAPI/IFunctionGeneral.h b/Framework/API/inc/MantidAPI/IFunctionGeneral.h
index f30a12f6808..b03027ecc5d 100644
--- a/Framework/API/inc/MantidAPI/IFunctionGeneral.h
+++ b/Framework/API/inc/MantidAPI/IFunctionGeneral.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFUNCTIONGENERAL_H_
-#define MANTID_API_IFUNCTIONGENERAL_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 
@@ -59,4 +58,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_IFUNCTIONGENERAL_H_ */
diff --git a/Framework/API/inc/MantidAPI/IFunctionMD.h b/Framework/API/inc/MantidAPI/IFunctionMD.h
index e99e8772200..3cb9932b7aa 100644
--- a/Framework/API/inc/MantidAPI/IFunctionMD.h
+++ b/Framework/API/inc/MantidAPI/IFunctionMD.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFUNCTIONMD_H_
-#define MANTID_API_IFUNCTIONMD_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -91,5 +90,3 @@ private:
 
 } // namespace API
 } // namespace Mantid
-
-#endif /*MANTID_API_IFUNCTIONMD_H_*/
diff --git a/Framework/API/inc/MantidAPI/IFunctionMW.h b/Framework/API/inc/MantidAPI/IFunctionMW.h
index 9fc9e363156..6a0d7ea8d48 100644
--- a/Framework/API/inc/MantidAPI/IFunctionMW.h
+++ b/Framework/API/inc/MantidAPI/IFunctionMW.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFUNCTIONMW_H_
-#define MANTID_API_IFUNCTIONMW_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -48,5 +47,3 @@ protected:
 
 } // namespace API
 } // namespace Mantid
-
-#endif /*MANTID_API_IFUNCTIONMW_H_*/
diff --git a/Framework/API/inc/MantidAPI/IFunctionWithLocation.h b/Framework/API/inc/MantidAPI/IFunctionWithLocation.h
index 87172ea11e8..4f21b2a6eb4 100644
--- a/Framework/API/inc/MantidAPI/IFunctionWithLocation.h
+++ b/Framework/API/inc/MantidAPI/IFunctionWithLocation.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IIFUNCTIONWITHLOCATION_H_
-#define MANTID_API_IIFUNCTIONWITHLOCATION_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -70,4 +69,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_IIFUNCTIONWITHLOCATION_H_*/
diff --git a/Framework/API/inc/MantidAPI/IFunction_fwd.h b/Framework/API/inc/MantidAPI/IFunction_fwd.h
index ca11c602df6..5a25072be5f 100644
--- a/Framework/API/inc/MantidAPI/IFunction_fwd.h
+++ b/Framework/API/inc/MantidAPI/IFunction_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IFUNCTION_FWD_H_
-#define IFUNCTION_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -42,4 +41,3 @@ using MultiDomainFunction_const_sptr =
 } // namespace API
 } // namespace Mantid
 
-#endif /* IFUNCTION_FWD_H_ */
diff --git a/Framework/API/inc/MantidAPI/ILatticeFunction.h b/Framework/API/inc/MantidAPI/ILatticeFunction.h
index f2eea27a2ef..3c825cfa874 100644
--- a/Framework/API/inc/MantidAPI/ILatticeFunction.h
+++ b/Framework/API/inc/MantidAPI/ILatticeFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ILATTICEFUNCTION_H_
-#define MANTID_API_ILATTICEFUNCTION_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/FunctionParameterDecorator.h"
@@ -57,4 +56,3 @@ using ILatticeFunction_sptr = boost::shared_ptr<ILatticeFunction>;
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_ILATTICEFUNCTION_H_ */
diff --git a/Framework/API/inc/MantidAPI/ILiveListener.h b/Framework/API/inc/MantidAPI/ILiveListener.h
index e64f2665e99..51f2047521f 100644
--- a/Framework/API/inc/MantidAPI/ILiveListener.h
+++ b/Framework/API/inc/MantidAPI/ILiveListener.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ILIVELISTENER_H_
-#define MANTID_API_ILIVELISTENER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -139,4 +138,3 @@ using ILiveListener_sptr = boost::shared_ptr<ILiveListener>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_ILIVELISTENER_H_*/
diff --git a/Framework/API/inc/MantidAPI/IMDEventWorkspace.h b/Framework/API/inc/MantidAPI/IMDEventWorkspace.h
index 60a559c9995..3604522adcb 100644
--- a/Framework/API/inc/MantidAPI/IMDEventWorkspace.h
+++ b/Framework/API/inc/MantidAPI/IMDEventWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMDEVENTWORKSPACE_H_
-#define IMDEVENTWORKSPACE_H_
+#pragma once
 
 #include "MantidAPI/BoxController.h"
 #include "MantidAPI/DllConfig.h"
@@ -135,4 +134,3 @@ private:
 
 } // namespace Mantid
 
-#endif /* IMDEVENTWORKSPACE_H_ */
diff --git a/Framework/API/inc/MantidAPI/IMDEventWorkspace_fwd.h b/Framework/API/inc/MantidAPI/IMDEventWorkspace_fwd.h
index f2576b6a593..73f9c730bc4 100644
--- a/Framework/API/inc/MantidAPI/IMDEventWorkspace_fwd.h
+++ b/Framework/API/inc/MantidAPI/IMDEventWorkspace_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMDEVENTWORKSPACE_FWD_H_
-#define IMDEVENTWORKSPACE_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -31,4 +30,3 @@ using IMDEventWorkspace_const_uptr = std::unique_ptr<const IMDEventWorkspace>;
 } // namespace API
 } // namespace Mantid
 
-#endif /* IMDEVENTWORKSPACE_FWD_H_ */
diff --git a/Framework/API/inc/MantidAPI/IMDHistoWorkspace.h b/Framework/API/inc/MantidAPI/IMDHistoWorkspace.h
index 048f8624cbd..e3e6fc266a9 100644
--- a/Framework/API/inc/MantidAPI/IMDHistoWorkspace.h
+++ b/Framework/API/inc/MantidAPI/IMDHistoWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IMDHISTOWORKSPACE_H_
-#define MANTID_API_IMDHISTOWORKSPACE_H_
+#pragma once
 
 #include "MantidAPI/IMDHistoWorkspace_fwd.h"
 #include "MantidAPI/IMDWorkspace.h"
@@ -114,4 +113,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_IMDHISTOWORKSPACE_H_ */
diff --git a/Framework/API/inc/MantidAPI/IMDHistoWorkspace_fwd.h b/Framework/API/inc/MantidAPI/IMDHistoWorkspace_fwd.h
index feab0eaa8b9..c03abd747b7 100644
--- a/Framework/API/inc/MantidAPI/IMDHistoWorkspace_fwd.h
+++ b/Framework/API/inc/MantidAPI/IMDHistoWorkspace_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IMDHISTOWORKSPACE_FWD_H_
-#define MANTID_API_IMDHISTOWORKSPACE_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -30,4 +29,3 @@ using IMDHistoWorkspace_const_uptr = std::unique_ptr<const IMDHistoWorkspace>;
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_IMDHISTOWORKSPACE_FWD_H_ */
diff --git a/Framework/API/inc/MantidAPI/IMDIterator.h b/Framework/API/inc/MantidAPI/IMDIterator.h
index 0f8c4cb1f39..861267398c5 100644
--- a/Framework/API/inc/MantidAPI/IMDIterator.h
+++ b/Framework/API/inc/MantidAPI/IMDIterator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFMDITERATOR_H_
-#define MANTID_API_IFMDITERATOR_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -128,4 +127,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_IFMDITERATOR_H_*/
diff --git a/Framework/API/inc/MantidAPI/IMDNode.h b/Framework/API/inc/MantidAPI/IMDNode.h
index 97a29315194..acbf8a44f1f 100644
--- a/Framework/API/inc/MantidAPI/IMDNode.h
+++ b/Framework/API/inc/MantidAPI/IMDNode.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMD_NODE_H_
-#define IMD_NODE_H_
+#pragma once
 
 #include "MantidGeometry/MDGeometry/MDTypes.h"
 #include "MantidKernel/VMD.h"
@@ -317,4 +316,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif
diff --git a/Framework/API/inc/MantidAPI/IMDWorkspace.h b/Framework/API/inc/MantidAPI/IMDWorkspace.h
index 51fb1f40dc6..5ad8a9146b8 100644
--- a/Framework/API/inc/MantidAPI/IMDWorkspace.h
+++ b/Framework/API/inc/MantidAPI/IMDWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IMDWORKSPACE_H_
-#define MANTID_API_IMDWORKSPACE_H_
+#pragma once
 
 #include "MantidAPI/IMDIterator.h"
 #include "MantidAPI/ITableWorkspace_fwd.h"
@@ -166,4 +165,3 @@ using IMDWorkspace_sptr = boost::shared_ptr<IMDWorkspace>;
 using IMDWorkspace_const_sptr = boost::shared_ptr<const IMDWorkspace>;
 } // namespace API
 } // namespace Mantid
-#endif // MANTID_API_IMDWORKSPACE_H_
diff --git a/Framework/API/inc/MantidAPI/IMaskWorkspace.h b/Framework/API/inc/MantidAPI/IMaskWorkspace.h
index 414431987d4..d8868d44f50 100644
--- a/Framework/API/inc/MantidAPI/IMaskWorkspace.h
+++ b/Framework/API/inc/MantidAPI/IMaskWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IMASKWORKSPACE_H_
-#define MANTID_API_IMASKWORKSPACE_H_
+#pragma once
 
 #include "MantidGeometry/IDTypes.h"
 
@@ -57,4 +56,3 @@ using IMaskWorkspace_const_sptr = boost::shared_ptr<const IMaskWorkspace>;
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_IMASKWORKSPACE_H_
diff --git a/Framework/API/inc/MantidAPI/IPawleyFunction.h b/Framework/API/inc/MantidAPI/IPawleyFunction.h
index 91487f26d3d..c7f857c1d28 100644
--- a/Framework/API/inc/MantidAPI/IPawleyFunction.h
+++ b/Framework/API/inc/MantidAPI/IPawleyFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IPAWLEYFUNCTION_H_
-#define MANTID_API_IPAWLEYFUNCTION_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/FunctionParameterDecorator.h"
@@ -61,4 +60,3 @@ using IPawleyFunction_sptr = boost::shared_ptr<IPawleyFunction>;
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_IPAWLEYFUNCTION_H_ */
diff --git a/Framework/API/inc/MantidAPI/IPeakFunction.h b/Framework/API/inc/MantidAPI/IPeakFunction.h
index 24f4daea301..f92a5e69ed4 100644
--- a/Framework/API/inc/MantidAPI/IPeakFunction.h
+++ b/Framework/API/inc/MantidAPI/IPeakFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IPEAKFUNCTION_H_
-#define MANTID_API_IPEAKFUNCTION_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -94,4 +93,3 @@ using IPeakFunction_const_sptr = boost::shared_ptr<const IPeakFunction>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_IPEAKFUNCTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/IPeaksWorkspace.h b/Framework/API/inc/MantidAPI/IPeaksWorkspace.h
index 377cd288ed4..f34d276ceea 100644
--- a/Framework/API/inc/MantidAPI/IPeaksWorkspace.h
+++ b/Framework/API/inc/MantidAPI/IPeaksWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IPEAKSWORKSPACE_H_
-#define MANTID_API_IPEAKSWORKSPACE_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -177,4 +176,3 @@ private:
 };
 } // namespace API
 } // namespace Mantid
-#endif
diff --git a/Framework/API/inc/MantidAPI/IPeaksWorkspace_fwd.h b/Framework/API/inc/MantidAPI/IPeaksWorkspace_fwd.h
index 7b041b735d8..7f3be834cb3 100644
--- a/Framework/API/inc/MantidAPI/IPeaksWorkspace_fwd.h
+++ b/Framework/API/inc/MantidAPI/IPeaksWorkspace_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IPEAKWORKSPACE_FWD_H_
-#define MANTID_API_IPEAKWORKSPACE_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -28,4 +27,3 @@ using IPeaksWorkspace_uptr = std::unique_ptr<IPeaksWorkspace>;
 using IPeaksWorkspace_const_uptr = std::unique_ptr<const IPeaksWorkspace>;
 } // namespace API
 } // namespace Mantid
-#endif // MANTID_API_IPEAKWORKSPACE_FWD_H_
diff --git a/Framework/API/inc/MantidAPI/IPowderDiffPeakFunction.h b/Framework/API/inc/MantidAPI/IPowderDiffPeakFunction.h
index a3d62256a6a..c1891b03317 100644
--- a/Framework/API/inc/MantidAPI/IPowderDiffPeakFunction.h
+++ b/Framework/API/inc/MantidAPI/IPowderDiffPeakFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IPOWDERDIFFPEAKFUNCTION_H_
-#define MANTID_API_IPOWDERDIFFPEAKFUNCTION_H_
+#pragma once
 
 #include "MantidAPI/IFunction1D.h"
 #include "MantidAPI/ParamFunction.h"
@@ -152,4 +151,3 @@ std::complex<double> MANTID_API_DLL E1(std::complex<double> z);
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_IPOWDERDIFFPEAKFUNCTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/IRemoteJobManager.h b/Framework/API/inc/MantidAPI/IRemoteJobManager.h
index f80a7a799de..6149ba99994 100644
--- a/Framework/API/inc/MantidAPI/IRemoteJobManager.h
+++ b/Framework/API/inc/MantidAPI/IRemoteJobManager.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_KERNEL_IREMOTEJOBMANAGER_H
-#define MANTID_KERNEL_IREMOTEJOBMANAGER_H
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidKernel/DateAndTime.h"
@@ -279,4 +278,3 @@ using IRemoteJobManager_sptr = boost::shared_ptr<IRemoteJobManager>;
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_IREMOTEJOBMANAGER_H
diff --git a/Framework/API/inc/MantidAPI/ISpectrum.h b/Framework/API/inc/MantidAPI/ISpectrum.h
index 1f3c03b6483..aed11cee5f0 100644
--- a/Framework/API/inc/MantidAPI/ISpectrum.h
+++ b/Framework/API/inc/MantidAPI/ISpectrum.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ISPECTRUM_H_
-#define MANTID_API_ISPECTRUM_H_
+#pragma once
 
 #include "MantidGeometry/IDTypes.h"
 #include "MantidHistogramData/Histogram.h"
@@ -271,4 +270,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_ISPECTRUM_H_ */
diff --git a/Framework/API/inc/MantidAPI/ISplittersWorkspace.h b/Framework/API/inc/MantidAPI/ISplittersWorkspace.h
index 6d81d65c4eb..5ba645f3dea 100644
--- a/Framework/API/inc/MantidAPI/ISplittersWorkspace.h
+++ b/Framework/API/inc/MantidAPI/ISplittersWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ISPLITTERSWORKSPACE_H_
-#define MANTID_API_ISPLITTERSWORKSPACE_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidKernel/TimeSplitter.h"
@@ -73,4 +72,3 @@ using ISplittersWorkspace_const_sptr =
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_ISPLITTERSWORKSPACE_H_ */
diff --git a/Framework/API/inc/MantidAPI/ITableWorkspace.h b/Framework/API/inc/MantidAPI/ITableWorkspace.h
index 3a063107139..a3b12c839cf 100644
--- a/Framework/API/inc/MantidAPI/ITableWorkspace.h
+++ b/Framework/API/inc/MantidAPI/ITableWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ITABLEWORKSPACE_H_
-#define MANTID_API_ITABLEWORKSPACE_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -410,4 +409,3 @@ private:
 
 } // namespace API
 } // Namespace Mantid
-#endif /*MANTID_API_ITABLEWORKSPACE_H_*/
diff --git a/Framework/API/inc/MantidAPI/ITableWorkspace_fwd.h b/Framework/API/inc/MantidAPI/ITableWorkspace_fwd.h
index 0412c4c6291..83265ade539 100644
--- a/Framework/API/inc/MantidAPI/ITableWorkspace_fwd.h
+++ b/Framework/API/inc/MantidAPI/ITableWorkspace_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ITABLEWORKSPACE_FWD_H_
-#define MANTID_API_ITABLEWORKSPACE_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -29,4 +28,3 @@ using ITableWorkspace_const_uptr = std::unique_ptr<const ITableWorkspace>;
 
 } // namespace API
 } // Namespace Mantid
-#endif // MANTID_API_ITABLEWORKSPACE_FWD_H_
diff --git a/Framework/API/inc/MantidAPI/ITransformScale.h b/Framework/API/inc/MantidAPI/ITransformScale.h
index 61ac7580411..abb06dbbb24 100644
--- a/Framework/API/inc/MantidAPI/ITransformScale.h
+++ b/Framework/API/inc/MantidAPI/ITransformScale.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ITRANSFORMSCALE_H_
-#define MANTID_API_ITRANSFORMSCALE_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -51,5 +50,3 @@ using ITransformScale_sptr = boost::shared_ptr<ITransformScale>;
            #classname)),                                                       \
        0));                                                                    \
   }
-
-#endif /*MANTID_API_ITRANSFORMSCALE_H_*/
diff --git a/Framework/API/inc/MantidAPI/IWorkspaceProperty.h b/Framework/API/inc/MantidAPI/IWorkspaceProperty.h
index d45d393cefd..439df3f4d48 100644
--- a/Framework/API/inc/MantidAPI/IWorkspaceProperty.h
+++ b/Framework/API/inc/MantidAPI/IWorkspaceProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IWORKSPACEPROPERTY_H_
-#define MANTID_API_IWORKSPACEPROPERTY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -42,4 +41,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_IWORKSPACEPROPERTY_H_*/
diff --git a/Framework/API/inc/MantidAPI/ImmutableCompositeFunction.h b/Framework/API/inc/MantidAPI/ImmutableCompositeFunction.h
index 486fac7da1e..c8dddefdbbe 100644
--- a/Framework/API/inc/MantidAPI/ImmutableCompositeFunction.h
+++ b/Framework/API/inc/MantidAPI/ImmutableCompositeFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IMMUTABLECOMPOSITEFUNCTION_H_
-#define MANTID_API_IMMUTABLECOMPOSITEFUNCTION_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -80,4 +79,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_IMMUTABLECOMPOSITEFUNCTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/ImplicitFunctionBuilder.h b/Framework/API/inc/MantidAPI/ImplicitFunctionBuilder.h
index d98bcfbd53a..5387970f5a0 100644
--- a/Framework/API/inc/MantidAPI/ImplicitFunctionBuilder.h
+++ b/Framework/API/inc/MantidAPI/ImplicitFunctionBuilder.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IFUNCTONBUILDER_H_
-#define IFUNCTONBUILDER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -32,4 +31,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif
diff --git a/Framework/API/inc/MantidAPI/ImplicitFunctionFactory.h b/Framework/API/inc/MantidAPI/ImplicitFunctionFactory.h
index cf42731a2f4..429f6e02d63 100644
--- a/Framework/API/inc/MantidAPI/ImplicitFunctionFactory.h
+++ b/Framework/API/inc/MantidAPI/ImplicitFunctionFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMPLICIT_FUNCTION_FACTORY
-#define IMPLICIT_FUNCTION_FACTORY
+#pragma once
 
 /** @class ImplicitFunctionFactory ImplicitFunctionFactory.h
 Kernel/ImplicitFunctionFactory.h
@@ -61,4 +60,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif
diff --git a/Framework/API/inc/MantidAPI/ImplicitFunctionParameter.h b/Framework/API/inc/MantidAPI/ImplicitFunctionParameter.h
index dd95b4bc98b..2559b5e2423 100644
--- a/Framework/API/inc/MantidAPI/ImplicitFunctionParameter.h
+++ b/Framework/API/inc/MantidAPI/ImplicitFunctionParameter.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IPARAMETER_H_
-#define IPARAMETER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -138,5 +137,3 @@ template <> struct ElementTraits<float> {
 //------------------------------------------------------------------------------------
 } // namespace API
 } // namespace Mantid
-
-#endif
diff --git a/Framework/API/inc/MantidAPI/ImplicitFunctionParameterParser.h b/Framework/API/inc/MantidAPI/ImplicitFunctionParameterParser.h
index 9e43147192c..9acd68eb2f8 100644
--- a/Framework/API/inc/MantidAPI/ImplicitFunctionParameterParser.h
+++ b/Framework/API/inc/MantidAPI/ImplicitFunctionParameterParser.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef PARAMETER_PARSER_H_
-#define PARAMETER_PARSER_H_
+#pragma once
 
 /* Used to register classes into the factory. creates a global object in an
  * anonymous namespace. The object itself does nothing, but the comma operator
@@ -81,5 +80,3 @@ protected:
 };
 } // namespace API
 } // namespace Mantid
-
-#endif
diff --git a/Framework/API/inc/MantidAPI/ImplicitFunctionParameterParserFactory.h b/Framework/API/inc/MantidAPI/ImplicitFunctionParameterParserFactory.h
index 05a046a9c64..64619f8ac04 100644
--- a/Framework/API/inc/MantidAPI/ImplicitFunctionParameterParserFactory.h
+++ b/Framework/API/inc/MantidAPI/ImplicitFunctionParameterParserFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMPLICIT_FUNCTION_PARAMETER_PARSER_FACTORY_H
-#define IMPLICIT_FUNCTION_PARAMETER_PARSER_FACTORY_H
+#pragma once
 
 /** @class ImplicitFunctionFactory ImplicitFunctionFactory.h
 Kernel/ImplicitFunctionFactory.h
@@ -59,4 +58,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL Mantid::Kernel::SingletonHolder<
 }
 } // namespace Mantid
 
-#endif
diff --git a/Framework/API/inc/MantidAPI/ImplicitFunctionParser.h b/Framework/API/inc/MantidAPI/ImplicitFunctionParser.h
index 262e35487fa..f3d1162775e 100644
--- a/Framework/API/inc/MantidAPI/ImplicitFunctionParser.h
+++ b/Framework/API/inc/MantidAPI/ImplicitFunctionParser.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FUNCTION_ABSTRACT_PARSER_H_
-#define FUNCTION_ABSTRACT_PARSER_H_
+#pragma once
 
 /* Used to register classes into the factory. creates a global object in an
  * anonymous namespace. The object itself does nothing, but the comma operator
@@ -88,4 +87,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif
diff --git a/Framework/API/inc/MantidAPI/ImplicitFunctionParserFactory.h b/Framework/API/inc/MantidAPI/ImplicitFunctionParserFactory.h
index b485e97cff6..a80b1408401 100644
--- a/Framework/API/inc/MantidAPI/ImplicitFunctionParserFactory.h
+++ b/Framework/API/inc/MantidAPI/ImplicitFunctionParserFactory.h
@@ -5,8 +5,7 @@
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
 
-#ifndef IMPLICIT_FUNCTION_PARSER_FACTORY
-#define IMPLICIT_FUNCTION_PARSER_FACTORY
+#pragma once
 
 /** @class ImplicitFunctionParserFactory ImplicitFunctionParserFactory.h
    Kernel/ImplicitFunctionParserFactory.h
@@ -63,4 +62,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL Mantid::Kernel::SingletonHolder<
 }
 } // namespace Mantid
 
-#endif
diff --git a/Framework/API/inc/MantidAPI/IncreasingAxisValidator.h b/Framework/API/inc/MantidAPI/IncreasingAxisValidator.h
index 97866499b58..27db54b39dc 100644
--- a/Framework/API/inc/MantidAPI/IncreasingAxisValidator.h
+++ b/Framework/API/inc/MantidAPI/IncreasingAxisValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_INCREASINGAXISVALIDATOR_H_
-#define MANTID_API_INCREASINGAXISVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceValidator.h"
 
@@ -31,4 +30,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_INCREASINGAXISVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/IndexProperty.h b/Framework/API/inc/MantidAPI/IndexProperty.h
index c17e0814b92..e4d3bcfa2e3 100644
--- a/Framework/API/inc/MantidAPI/IndexProperty.h
+++ b/Framework/API/inc/MantidAPI/IndexProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_INDEXPROPERTY_H_
-#define MANTID_API_INDEXPROPERTY_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/IWorkspaceProperty.h"
@@ -63,4 +62,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_INDEXPROPERTY_H_ */
diff --git a/Framework/API/inc/MantidAPI/IndexTypeProperty.h b/Framework/API/inc/MantidAPI/IndexTypeProperty.h
index ac03cdeeee8..830ebf5430e 100644
--- a/Framework/API/inc/MantidAPI/IndexTypeProperty.h
+++ b/Framework/API/inc/MantidAPI/IndexTypeProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_INDEXTYPEPROPERTY_H_
-#define MANTID_API_INDEXTYPEPROPERTY_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidKernel/PropertyWithValue.h"
@@ -49,4 +48,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_INDEXTYPEPROPERTY_H_ */
diff --git a/Framework/API/inc/MantidAPI/InstrumentDataService.h b/Framework/API/inc/MantidAPI/InstrumentDataService.h
index 02bbf2548b6..07ecdf9ca91 100644
--- a/Framework/API/inc/MantidAPI/InstrumentDataService.h
+++ b/Framework/API/inc/MantidAPI/InstrumentDataService.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_INSTRUMENTDATASERVICE_
-#define MANTID_API_INSTRUMENTDATASERVICE_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidGeometry/Instrument.h"
@@ -46,4 +45,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /*INSTRUMENTDATASERVICE_*/
diff --git a/Framework/API/inc/MantidAPI/InstrumentValidator.h b/Framework/API/inc/MantidAPI/InstrumentValidator.h
index 2e6c916901e..3953752e4e0 100644
--- a/Framework/API/inc/MantidAPI/InstrumentValidator.h
+++ b/Framework/API/inc/MantidAPI/InstrumentValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_INSTRUMENTVALIDATOR_H_
-#define MANTID_API_INSTRUMENTVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/ExperimentInfo.h"
@@ -39,4 +38,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_INSTRUMENTVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/Jacobian.h b/Framework/API/inc/MantidAPI/Jacobian.h
index 779004363df..44acf84a63e 100644
--- a/Framework/API/inc/MantidAPI/Jacobian.h
+++ b/Framework/API/inc/MantidAPI/Jacobian.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_JACOBIAN_H_
-#define MANTID_API_JACOBIAN_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -60,4 +59,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_JACOBIAN_H_*/
diff --git a/Framework/API/inc/MantidAPI/JointDomain.h b/Framework/API/inc/MantidAPI/JointDomain.h
index 6b248e396b5..a9b48f92a37 100644
--- a/Framework/API/inc/MantidAPI/JointDomain.h
+++ b/Framework/API/inc/MantidAPI/JointDomain.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_JOINTDOMAIN_H_
-#define MANTID_API_JOINTDOMAIN_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -42,4 +41,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_JOINTDOMAIN_H_*/
diff --git a/Framework/API/inc/MantidAPI/LatticeDomain.h b/Framework/API/inc/MantidAPI/LatticeDomain.h
index 0232181e63d..62681ac09af 100644
--- a/Framework/API/inc/MantidAPI/LatticeDomain.h
+++ b/Framework/API/inc/MantidAPI/LatticeDomain.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_LATTICEDOMAIN_H_
-#define MANTID_API_LATTICEDOMAIN_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/FunctionDomain.h"
@@ -37,4 +36,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_LATTICEDOMAIN_H_ */
diff --git a/Framework/API/inc/MantidAPI/LinearScale.h b/Framework/API/inc/MantidAPI/LinearScale.h
index 4c2084a9e52..543c26afafb 100644
--- a/Framework/API/inc/MantidAPI/LinearScale.h
+++ b/Framework/API/inc/MantidAPI/LinearScale.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_LINEARSCALE_H_
-#define MANTID_API_LINEARSCALE_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -35,4 +34,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_LINEARSCALE_H_*/
diff --git a/Framework/API/inc/MantidAPI/LiveListener.h b/Framework/API/inc/MantidAPI/LiveListener.h
index 1197b7af056..74fa6859f53 100644
--- a/Framework/API/inc/MantidAPI/LiveListener.h
+++ b/Framework/API/inc/MantidAPI/LiveListener.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_LIVELISTENER_H_
-#define MANTID_API_LIVELISTENER_H_
+#pragma once
 
 #include "MantidAPI/ILiveListener.h"
 
@@ -29,4 +28,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_LIVELISTENER_H_ */
diff --git a/Framework/API/inc/MantidAPI/LiveListenerFactory.h b/Framework/API/inc/MantidAPI/LiveListenerFactory.h
index e7e403ad07e..63d1d020505 100644
--- a/Framework/API/inc/MantidAPI/LiveListenerFactory.h
+++ b/Framework/API/inc/MantidAPI/LiveListenerFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_LIVELISTENERFACTORYIMPL_H_
-#define MANTID_API_LIVELISTENERFACTORYIMPL_H_
+#pragma once
 
 /* Used to register unit classes into the factory. creates a global object in an
  * anonymous namespace. The object itself does nothing, but the comma operator
@@ -80,4 +79,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /* MANTID_API_LIVELISTENERFACTORYIMPL_H_ */
diff --git a/Framework/API/inc/MantidAPI/LogFilterGenerator.h b/Framework/API/inc/MantidAPI/LogFilterGenerator.h
index 2a454338a74..4b05f4be3bf 100644
--- a/Framework/API/inc/MantidAPI/LogFilterGenerator.h
+++ b/Framework/API/inc/MantidAPI/LogFilterGenerator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_LOGFILTERGENERATOR_H_
-#define MANTID_API_LOGFILTERGENERATOR_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/MatrixWorkspace_fwd.h"
@@ -55,4 +54,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_LOGFILTERGENERATOR_H_ */
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/LogManager.h b/Framework/API/inc/MantidAPI/LogManager.h
index f1148286640..925d0963e05 100644
--- a/Framework/API/inc/MantidAPI/LogManager.h
+++ b/Framework/API/inc/MantidAPI/LogManager.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_LOGMANAGER_H_
-#define MANTID_API_LOGMANAGER_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidKernel/PropertyWithValue.h"
@@ -237,4 +236,3 @@ void LogManager::addProperty(const std::string &name, const TYPE &value,
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_LOGMANAGER_H_
diff --git a/Framework/API/inc/MantidAPI/LogarithmScale.h b/Framework/API/inc/MantidAPI/LogarithmScale.h
index 4cc6c42a968..9dad793fa63 100644
--- a/Framework/API/inc/MantidAPI/LogarithmScale.h
+++ b/Framework/API/inc/MantidAPI/LogarithmScale.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_LOGARITHMSCALE_H_
-#define MANTID_API_LOGARITHMSCALE_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -42,4 +41,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_LOGARITHMSCALE_H_*/
diff --git a/Framework/API/inc/MantidAPI/MDFrameValidator.h b/Framework/API/inc/MantidAPI/MDFrameValidator.h
index 951a4d27ae1..be940b62099 100644
--- a/Framework/API/inc/MantidAPI/MDFrameValidator.h
+++ b/Framework/API/inc/MantidAPI/MDFrameValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MDFRAMEVALIDATOR_H
-#define MANTID_API_MDFRAMEVALIDATOR_H
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/IMDWorkspace.h"
@@ -37,4 +36,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_MDFRAMEVALIDATOR_H
diff --git a/Framework/API/inc/MantidAPI/MDGeometry.h b/Framework/API/inc/MantidAPI/MDGeometry.h
index f0b429c7495..efc9959c027 100644
--- a/Framework/API/inc/MantidAPI/MDGeometry.h
+++ b/Framework/API/inc/MantidAPI/MDGeometry.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MDGEOMETRY_H_
-#define MANTID_API_MDGEOMETRY_H_
+#pragma once
 
 #include "MantidGeometry/MDGeometry/MDTypes.h"
 #include "MantidKernel/Matrix.h"
@@ -168,4 +167,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_MDGEOMETRY_H_ */
diff --git a/Framework/API/inc/MantidAPI/MatrixWorkspace.h b/Framework/API/inc/MantidAPI/MatrixWorkspace.h
index e978fc9e06a..149614af973 100644
--- a/Framework/API/inc/MantidAPI/MatrixWorkspace.h
+++ b/Framework/API/inc/MantidAPI/MatrixWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MATRIXWORKSPACE_H_
-#define MANTID_API_MATRIXWORKSPACE_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/ExperimentInfo.h"
@@ -635,4 +634,3 @@ using MatrixWorkspace_const_sptr = boost::shared_ptr<const MatrixWorkspace>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_MATRIXWORKSPACE_H_*/
diff --git a/Framework/API/inc/MantidAPI/MatrixWorkspaceMDIterator.h b/Framework/API/inc/MantidAPI/MatrixWorkspaceMDIterator.h
index d6d1992de5d..274b983a1d7 100644
--- a/Framework/API/inc/MantidAPI/MatrixWorkspaceMDIterator.h
+++ b/Framework/API/inc/MantidAPI/MatrixWorkspaceMDIterator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MATRIXWORKSPACEMDITERATOR_H_
-#define MANTID_API_MATRIXWORKSPACEMDITERATOR_H_
+#pragma once
 
 #include "MantidAPI/IMDIterator.h"
 #include "MantidAPI/MatrixWorkspace_fwd.h"
@@ -134,4 +133,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_MATRIXWORKSPACEMDITERATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/MatrixWorkspaceValidator.h b/Framework/API/inc/MantidAPI/MatrixWorkspaceValidator.h
index 99150304993..ae106c642f3 100644
--- a/Framework/API/inc/MantidAPI/MatrixWorkspaceValidator.h
+++ b/Framework/API/inc/MantidAPI/MatrixWorkspaceValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MATRIXWORKSPACEVALIDATOR_H_
-#define MANTID_API_MATRIXWORKSPACEVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/MatrixWorkspace.h"
@@ -23,4 +22,3 @@ class MANTID_API_DLL MatrixWorkspaceValidator
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_MATRIXWORKSPACEVALIDATOR_H_ */
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/MatrixWorkspace_fwd.h b/Framework/API/inc/MantidAPI/MatrixWorkspace_fwd.h
index 1efb41896f5..c81672c25a7 100644
--- a/Framework/API/inc/MantidAPI/MatrixWorkspace_fwd.h
+++ b/Framework/API/inc/MantidAPI/MatrixWorkspace_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MATRIXWORKSPACE_FWD_H_
-#define MANTID_API_MATRIXWORKSPACE_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -30,4 +29,3 @@ using MatrixWorkspace_const_uptr = std::unique_ptr<const MatrixWorkspace>;
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_MATRIXWORKSPACE_FWD_H_
diff --git a/Framework/API/inc/MantidAPI/MuParserUtils.h b/Framework/API/inc/MantidAPI/MuParserUtils.h
index da0cb80466c..02f7ecd3e5a 100644
--- a/Framework/API/inc/MantidAPI/MuParserUtils.h
+++ b/Framework/API/inc/MantidAPI/MuParserUtils.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MUPARSERUTILS_H_
-#define MANTID_API_MUPARSERUTILS_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -37,4 +36,3 @@ void MANTID_API_DLL extraOneVarFunctions(mu::Parser &parser);
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_MUPARSERUTILS_H_ */
diff --git a/Framework/API/inc/MantidAPI/MultiDomainFunction.h b/Framework/API/inc/MantidAPI/MultiDomainFunction.h
index 85ed522428e..3311dcd26f4 100644
--- a/Framework/API/inc/MantidAPI/MultiDomainFunction.h
+++ b/Framework/API/inc/MantidAPI/MultiDomainFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MULTIDOMAINFUNCTION_H_
-#define MANTID_API_MULTIDOMAINFUNCTION_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -101,4 +100,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_MULTIDOMAINFUNCTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/MultiPeriodGroupAlgorithm.h b/Framework/API/inc/MantidAPI/MultiPeriodGroupAlgorithm.h
index 616836dcb7c..d222f89e481 100644
--- a/Framework/API/inc/MantidAPI/MultiPeriodGroupAlgorithm.h
+++ b/Framework/API/inc/MantidAPI/MultiPeriodGroupAlgorithm.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MUTLIPERIODGROUPALGORITHM_H_
-#define MANTID_API_MUTLIPERIODGROUPALGORITHM_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/MultiPeriodGroupWorker.h"
@@ -47,4 +46,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_MUTLIPERIODGROUPALGORITHM_H_ */
diff --git a/Framework/API/inc/MantidAPI/MultiPeriodGroupWorker.h b/Framework/API/inc/MantidAPI/MultiPeriodGroupWorker.h
index 87bc088c1ec..ff9debdd054 100644
--- a/Framework/API/inc/MantidAPI/MultiPeriodGroupWorker.h
+++ b/Framework/API/inc/MantidAPI/MultiPeriodGroupWorker.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MULTIPERIODGROUPWORKER_H_
-#define MANTID_API_MULTIPERIODGROUPWORKER_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/WorkspaceGroup_fwd.h"
@@ -77,4 +76,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_MULTIPERIODGROUPWORKER_H_ */
diff --git a/Framework/API/inc/MantidAPI/MultipleExperimentInfos.h b/Framework/API/inc/MantidAPI/MultipleExperimentInfos.h
index 91a4a02b96e..0a0fbe4e9c3 100644
--- a/Framework/API/inc/MantidAPI/MultipleExperimentInfos.h
+++ b/Framework/API/inc/MantidAPI/MultipleExperimentInfos.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MULTIPLEEXPERIMENTINFOS_H_
-#define MANTID_API_MULTIPLEEXPERIMENTINFOS_H_
+#pragma once
 
 #include "MantidAPI/ExperimentInfo.h"
 #include "MantidKernel/System.h"
@@ -55,4 +54,3 @@ using MultipleExperimentInfos_const_sptr =
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_MULTIPLEEXPERIMENTINFOS_H_ */
diff --git a/Framework/API/inc/MantidAPI/MultipleFileProperty.h b/Framework/API/inc/MantidAPI/MultipleFileProperty.h
index 06df859311d..a91825315e3 100644
--- a/Framework/API/inc/MantidAPI/MultipleFileProperty.h
+++ b/Framework/API/inc/MantidAPI/MultipleFileProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MULTIPLEFILEPROPERTY_H_
-#define MANTID_API_MULTIPLEFILEPROPERTY_H_
+#pragma once
 
 #include "MantidKernel/MultiFileNameParser.h"
 #include "MantidKernel/PropertyWithValue.h"
@@ -175,4 +174,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_MULTIPLEFILEPROPERTY_H_ */
diff --git a/Framework/API/inc/MantidAPI/NotebookBuilder.h b/Framework/API/inc/MantidAPI/NotebookBuilder.h
index 95294f65f41..304dd33296f 100644
--- a/Framework/API/inc/MantidAPI/NotebookBuilder.h
+++ b/Framework/API/inc/MantidAPI/NotebookBuilder.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_NOTEBOOKBUILDER_H_
-#define MANTID_API_NOTEBOOKBUILDER_H_
+#pragma once
 
 /** @class NotebookBuilder
 
@@ -51,4 +50,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_NOTEBOOKBUILDER_H_*/
diff --git a/Framework/API/inc/MantidAPI/NotebookWriter.h b/Framework/API/inc/MantidAPI/NotebookWriter.h
index cc81a195ba0..2593ef14d24 100644
--- a/Framework/API/inc/MantidAPI/NotebookWriter.h
+++ b/Framework/API/inc/MantidAPI/NotebookWriter.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_NOTEBOOKWRITER_H
-#define MANTID_NOTEBOOKWRITER_H
+#pragma once
 
 /** @class NotebookWriter
 
@@ -43,4 +42,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_NOTEBOOKWRITER_H
diff --git a/Framework/API/inc/MantidAPI/NullCoordTransform.h b/Framework/API/inc/MantidAPI/NullCoordTransform.h
index 7a5f1a4dc28..59e8e7c292f 100644
--- a/Framework/API/inc/MantidAPI/NullCoordTransform.h
+++ b/Framework/API/inc/MantidAPI/NullCoordTransform.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTIDAPI_NULLCOORDTRANSFORM_H
-#define MANTIDAPI_NULLCOORDTRANSFORM_H
+#pragma once
 
 #include "MantidAPI/CoordTransform.h"
 
@@ -34,4 +33,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif
diff --git a/Framework/API/inc/MantidAPI/NumericAxis.h b/Framework/API/inc/MantidAPI/NumericAxis.h
index db1e4d0ccf0..886cb299e4e 100644
--- a/Framework/API/inc/MantidAPI/NumericAxis.h
+++ b/Framework/API/inc/MantidAPI/NumericAxis.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_NUMERICAXIS_H_
-#define MANTID_API_NUMERICAXIS_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -72,4 +71,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_NUMERICAXIS_H_ */
diff --git a/Framework/API/inc/MantidAPI/NumericAxisValidator.h b/Framework/API/inc/MantidAPI/NumericAxisValidator.h
index a228afbd370..df97ba9bbfb 100644
--- a/Framework/API/inc/MantidAPI/NumericAxisValidator.h
+++ b/Framework/API/inc/MantidAPI/NumericAxisValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_NUMERICAXISVALIDATOR_H_
-#define MANTID_API_NUMERICAXISVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceValidator.h"
 
@@ -35,4 +34,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_NUMERICAXISVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/OrientedLatticeValidator.h b/Framework/API/inc/MantidAPI/OrientedLatticeValidator.h
index d890c68fe9d..f6bae5966b5 100644
--- a/Framework/API/inc/MantidAPI/OrientedLatticeValidator.h
+++ b/Framework/API/inc/MantidAPI/OrientedLatticeValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ORIENTEDLATTICEVALIDATOR_H
-#define MANTID_API_ORIENTEDLATTICEVALIDATOR_H
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/ExperimentInfo.h"
@@ -34,4 +33,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_ORIENTEDLATTICEVALIDATOR_H
diff --git a/Framework/API/inc/MantidAPI/ParallelAlgorithm.h b/Framework/API/inc/MantidAPI/ParallelAlgorithm.h
index 7c52fcfb359..8d6be0ee81f 100644
--- a/Framework/API/inc/MantidAPI/ParallelAlgorithm.h
+++ b/Framework/API/inc/MantidAPI/ParallelAlgorithm.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_PARALLELALGORITHM_H_
-#define MANTID_API_PARALLELALGORITHM_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/DllConfig.h"
@@ -40,4 +39,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_PARALLELALGORITHM_H_ */
diff --git a/Framework/API/inc/MantidAPI/ParamFunction.h b/Framework/API/inc/MantidAPI/ParamFunction.h
index 78be03e4580..615f5e6b246 100644
--- a/Framework/API/inc/MantidAPI/ParamFunction.h
+++ b/Framework/API/inc/MantidAPI/ParamFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_PARAMFUNCTION_H_
-#define MANTID_API_PARAMFUNCTION_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -116,4 +115,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_PARAMFUNCTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/ParameterReference.h b/Framework/API/inc/MantidAPI/ParameterReference.h
index 2689db24760..e0995261d44 100644
--- a/Framework/API/inc/MantidAPI/ParameterReference.h
+++ b/Framework/API/inc/MantidAPI/ParameterReference.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_PARAMETERREFERENCE_H_
-#define MANTID_API_PARAMETERREFERENCE_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -58,4 +57,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_PARAMETERREFERENCE_H_*/
diff --git a/Framework/API/inc/MantidAPI/ParameterTie.h b/Framework/API/inc/MantidAPI/ParameterTie.h
index a0c51c7fbee..4134ea15686 100644
--- a/Framework/API/inc/MantidAPI/ParameterTie.h
+++ b/Framework/API/inc/MantidAPI/ParameterTie.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_PARAMETERTIE_H_
-#define MANTID_API_PARAMETERTIE_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -73,4 +72,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_PARAMETERTIE_H_*/
diff --git a/Framework/API/inc/MantidAPI/PeakFunctionIntegrator.h b/Framework/API/inc/MantidAPI/PeakFunctionIntegrator.h
index e9c0ea481af..5baf433fe0a 100644
--- a/Framework/API/inc/MantidAPI/PeakFunctionIntegrator.h
+++ b/Framework/API/inc/MantidAPI/PeakFunctionIntegrator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef PEAKFUNCTIONINTEGRATOR_H
-#define PEAKFUNCTIONINTEGRATOR_H
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/IPeakFunction.h"
@@ -64,4 +63,3 @@ double MANTID_API_DLL gsl_peak_wrapper(double x, void *parameters);
 } // namespace API
 } // namespace Mantid
 
-#endif // PEAKFUNCTIONINTEGRATOR_H
diff --git a/Framework/API/inc/MantidAPI/PrecompiledHeader.h b/Framework/API/inc/MantidAPI/PrecompiledHeader.h
index 377951c4427..01f2a9561a1 100644
--- a/Framework/API/inc/MantidAPI/PrecompiledHeader.h
+++ b/Framework/API/inc/MantidAPI/PrecompiledHeader.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_PRECOMPILED_HEADER_H_
-#define MANTID_API_PRECOMPILED_HEADER_H_
+#pragma once
 
 // Mantid
 #include "MantidGeometry/IComponent.h"
@@ -39,4 +38,3 @@
 #include <Poco/DOM/DOMParser.h>
 #include <Poco/XML/XML.h>
 
-#endif // MANTID_API_PRECOMPILED_HEADER_H_
diff --git a/Framework/API/inc/MantidAPI/Progress.h b/Framework/API/inc/MantidAPI/Progress.h
index 9f9547c0434..5c16e6fd417 100644
--- a/Framework/API/inc/MantidAPI/Progress.h
+++ b/Framework/API/inc/MantidAPI/Progress.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_PROGRESS_H_
-#define MANTID_API_PROGRESS_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -41,4 +40,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_PROGRESS_H_*/
diff --git a/Framework/API/inc/MantidAPI/Projection.h b/Framework/API/inc/MantidAPI/Projection.h
index 7f44c118df1..f5ac34462cd 100644
--- a/Framework/API/inc/MantidAPI/Projection.h
+++ b/Framework/API/inc/MantidAPI/Projection.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_PROJECTION_H_
-#define MANTID_API_PROJECTION_H_
+#pragma once
 
 #include "MantidAPI/ITableWorkspace_fwd.h"
 #include "MantidKernel/V3D.h"
@@ -72,4 +71,3 @@ using Projection_sptr = boost::shared_ptr<Projection>;
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_PROJECTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/RawCountValidator.h b/Framework/API/inc/MantidAPI/RawCountValidator.h
index 91480d9726c..e994fce1c69 100644
--- a/Framework/API/inc/MantidAPI/RawCountValidator.h
+++ b/Framework/API/inc/MantidAPI/RawCountValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_RAWCOUNTVALIDATOR_H_
-#define MANTID_API_RAWCOUNTVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceValidator.h"
 
@@ -35,4 +34,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_RAWCOUNTVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/RefAxis.h b/Framework/API/inc/MantidAPI/RefAxis.h
index 241ea7ab14e..9d1c8926ccf 100644
--- a/Framework/API/inc/MantidAPI/RefAxis.h
+++ b/Framework/API/inc/MantidAPI/RefAxis.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_REFAXIS_H_
-#define MANTID_API_REFAXIS_H_
+#pragma once
 
 #include "MantidAPI/NumericAxis.h"
 
@@ -58,4 +57,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_REFAXIS_H_*/
diff --git a/Framework/API/inc/MantidAPI/RegisterFileLoader.h b/Framework/API/inc/MantidAPI/RegisterFileLoader.h
index cc2cad79b6f..74396f2b1cb 100644
--- a/Framework/API/inc/MantidAPI/RegisterFileLoader.h
+++ b/Framework/API/inc/MantidAPI/RegisterFileLoader.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_REGISTERFILELOADER_H_
-#define MANTID_API_REGISTERFILELOADER_H_
+#pragma once
 
 #include "MantidAPI/FileLoaderRegistry.h"
 
@@ -40,4 +39,3 @@
        0));                                                                    \
   }
 
-#endif /* MANTID_API_REGISTERFILELOADER_H_ */
diff --git a/Framework/API/inc/MantidAPI/RemoteJobManagerFactory.h b/Framework/API/inc/MantidAPI/RemoteJobManagerFactory.h
index 72174946adc..d8d2f407469 100644
--- a/Framework/API/inc/MantidAPI/RemoteJobManagerFactory.h
+++ b/Framework/API/inc/MantidAPI/RemoteJobManagerFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_REMOTEJOBMANAGERFACTORY_H_
-#define MANTID_API_REMOTEJOBMANAGERFACTORY_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/IRemoteJobManager.h"
@@ -99,4 +98,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
        0));                                                                    \
   }
 
-#endif // MANTID_API_REMOTEJOBMANAGERFACTORY_H_
diff --git a/Framework/API/inc/MantidAPI/ResizeRectangularDetectorHelper.h b/Framework/API/inc/MantidAPI/ResizeRectangularDetectorHelper.h
index 9cbf6445c00..5d9095ab28a 100644
--- a/Framework/API/inc/MantidAPI/ResizeRectangularDetectorHelper.h
+++ b/Framework/API/inc/MantidAPI/ResizeRectangularDetectorHelper.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_RESIZERECTANGULARDETECTORHELPER_H_
-#define MANTID_API_RESIZERECTANGULARDETECTORHELPER_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 
@@ -23,4 +22,3 @@ MANTID_API_DLL void applyRectangularDetectorScaleToComponentInfo(
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_RESIZERECTANGULARDETECTORHELPER_H_ */
diff --git a/Framework/API/inc/MantidAPI/Run.h b/Framework/API/inc/MantidAPI/Run.h
index bec42de7544..979f650069f 100644
--- a/Framework/API/inc/MantidAPI/Run.h
+++ b/Framework/API/inc/MantidAPI/Run.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_RUN_H_
-#define MANTID_API_RUN_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/LogManager.h"
@@ -111,4 +110,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTIDAPI_RUN_H_
diff --git a/Framework/API/inc/MantidAPI/Sample.h b/Framework/API/inc/MantidAPI/Sample.h
index 38eac2a75d2..247d2a70be2 100644
--- a/Framework/API/inc/MantidAPI/Sample.h
+++ b/Framework/API/inc/MantidAPI/Sample.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SAMPLE_H_
-#define MANTID_API_SAMPLE_H_
+#pragma once
 
 //-----------------------------------------------------------------------------
 // Includes
@@ -146,4 +145,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_SAMPLE_H_*/
diff --git a/Framework/API/inc/MantidAPI/SampleShapeValidator.h b/Framework/API/inc/MantidAPI/SampleShapeValidator.h
index 6a62d3b33cb..aea1ce66a63 100644
--- a/Framework/API/inc/MantidAPI/SampleShapeValidator.h
+++ b/Framework/API/inc/MantidAPI/SampleShapeValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SAMPLESHAPEVALIDATOR_H_
-#define MANTID_API_SAMPLESHAPEVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/ExperimentInfo.h"
@@ -32,4 +31,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SAMPLESHAPEVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/SampleValidator.h b/Framework/API/inc/MantidAPI/SampleValidator.h
index 3c8219b47e4..3dd9e4d9eb3 100644
--- a/Framework/API/inc/MantidAPI/SampleValidator.h
+++ b/Framework/API/inc/MantidAPI/SampleValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SAMPLEVALIDATOR_H_
-#define MANTID_API_SAMPLEVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceValidator.h"
 
@@ -32,4 +31,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SAMPLEVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/ScopedWorkspace.h b/Framework/API/inc/MantidAPI/ScopedWorkspace.h
index da4d2ac7f17..fef0b39bbf9 100644
--- a/Framework/API/inc/MantidAPI/ScopedWorkspace.h
+++ b/Framework/API/inc/MantidAPI/ScopedWorkspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SCOPEDWORKSPACE_H_
-#define MANTID_API_SCOPEDWORKSPACE_H_
+#pragma once
 
 #include <string>
 
@@ -80,4 +79,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SCOPEDWORKSPACE_H_ */
diff --git a/Framework/API/inc/MantidAPI/ScriptBuilder.h b/Framework/API/inc/MantidAPI/ScriptBuilder.h
index aca6c314b76..379f253b7dd 100644
--- a/Framework/API/inc/MantidAPI/ScriptBuilder.h
+++ b/Framework/API/inc/MantidAPI/ScriptBuilder.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SCRIPTBUILDER_H_
-#define MANTID_API_SCRIPTBUILDER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -69,4 +68,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_SCRIPTBUILDER_H_*/
diff --git a/Framework/API/inc/MantidAPI/ScriptRepository.h b/Framework/API/inc/MantidAPI/ScriptRepository.h
index 5a4535e3412..84e0ffd4725 100644
--- a/Framework/API/inc/MantidAPI/ScriptRepository.h
+++ b/Framework/API/inc/MantidAPI/ScriptRepository.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SCRIPTREPOSITORY_H_
-#define MANTID_API_SCRIPTREPOSITORY_H_
+#pragma once
 
 #include <string>
 #include <vector>
@@ -594,4 +593,3 @@ using ScriptRepository_sptr = boost::shared_ptr<ScriptRepository>;
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_SCRIPTREPOSITORY_H_
diff --git a/Framework/API/inc/MantidAPI/ScriptRepositoryFactory.h b/Framework/API/inc/MantidAPI/ScriptRepositoryFactory.h
index 9a9cc6fd3de..a4c67415734 100644
--- a/Framework/API/inc/MantidAPI/ScriptRepositoryFactory.h
+++ b/Framework/API/inc/MantidAPI/ScriptRepositoryFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SCRIPTREPOSITORYFACTORY_H_
-#define MANTID_API_SCRIPTREPOSITORYFACTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -78,4 +77,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
        0));                                                                    \
   }
 
-#endif /*MANTID_API_SCRIPTREPOSITORYFACTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/SerialAlgorithm.h b/Framework/API/inc/MantidAPI/SerialAlgorithm.h
index c21d91298c2..9e0a3af618d 100644
--- a/Framework/API/inc/MantidAPI/SerialAlgorithm.h
+++ b/Framework/API/inc/MantidAPI/SerialAlgorithm.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SERIALALGORITHM_H_
-#define MANTID_API_SERIALALGORITHM_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/DllConfig.h"
@@ -42,4 +41,3 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SERIALALGORITHM_H_ */
diff --git a/Framework/API/inc/MantidAPI/SingleCountValidator.h b/Framework/API/inc/MantidAPI/SingleCountValidator.h
index 0c3909f2544..35403427fdc 100644
--- a/Framework/API/inc/MantidAPI/SingleCountValidator.h
+++ b/Framework/API/inc/MantidAPI/SingleCountValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SINGLECOUNTVALIDATOR_H_
-#define MANTID_API_SINGLECOUNTVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceValidator.h"
 
@@ -37,4 +36,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SINGLECOUNTVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/SingleValueParameter.h b/Framework/API/inc/MantidAPI/SingleValueParameter.h
index 30cc781cca6..b91c7750b73 100644
--- a/Framework/API/inc/MantidAPI/SingleValueParameter.h
+++ b/Framework/API/inc/MantidAPI/SingleValueParameter.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_MDALGORITHMS_SingleValueParameter_H_
-#define MANTID_MDALGORITHMS_SingleValueParameter_H_
+#pragma once
 
 #include "MantidAPI/ImplicitFunctionParameter.h"
 #include "MantidKernel/System.h"
@@ -153,5 +152,3 @@ std::string SingleValueParameter<Derived, ValType>::toXMLString() const {
   };
 } // namespace API
 } // namespace Mantid
-
-#endif
diff --git a/Framework/API/inc/MantidAPI/SingleValueParameterParser.h b/Framework/API/inc/MantidAPI/SingleValueParameterParser.h
index 22db7d22958..dd43b5b93d3 100644
--- a/Framework/API/inc/MantidAPI/SingleValueParameterParser.h
+++ b/Framework/API/inc/MantidAPI/SingleValueParameterParser.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef SINGLE_VALUE_PARAMETER_PARSER_H_
-#define SINGLE_VALUE_PARAMETER_PARSER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -112,5 +111,3 @@ void SingleValueParameterParser<SingleValueParameterType>::setSuccessorParser(
 }
 } // namespace API
 } // namespace Mantid
-
-#endif
diff --git a/Framework/API/inc/MantidAPI/SpectraAxis.h b/Framework/API/inc/MantidAPI/SpectraAxis.h
index 8b8f1c5cf3c..53cc306ed83 100644
--- a/Framework/API/inc/MantidAPI/SpectraAxis.h
+++ b/Framework/API/inc/MantidAPI/SpectraAxis.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRAAXIS_H_
-#define MANTID_API_SPECTRAAXIS_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -70,4 +69,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SpectraAxis_H_ */
diff --git a/Framework/API/inc/MantidAPI/SpectraAxisValidator.h b/Framework/API/inc/MantidAPI/SpectraAxisValidator.h
index b73eeb29a9a..6b32a5ec072 100644
--- a/Framework/API/inc/MantidAPI/SpectraAxisValidator.h
+++ b/Framework/API/inc/MantidAPI/SpectraAxisValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRAAXISVALIDATOR_H_
-#define MANTID_API_SPECTRAAXISVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceValidator.h"
 
@@ -35,4 +34,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SPECTRAAXISVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/SpectraDetectorTypes.h b/Framework/API/inc/MantidAPI/SpectraDetectorTypes.h
index 8b5fdac3065..226a64cb6b3 100644
--- a/Framework/API/inc/MantidAPI/SpectraDetectorTypes.h
+++ b/Framework/API/inc/MantidAPI/SpectraDetectorTypes.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRADETECTORMAP_TYPES
-#define MANTID_API_SPECTRADETECTORMAP_TYPES
+#pragma once
 //------------------------------------------------------------------------------
 // Includes
 //------------------------------------------------------------------------------
@@ -23,4 +22,3 @@ using detid2index_map = std::unordered_map<detid_t, size_t>;
 using det2group_map = std::unordered_map<detid_t, std::set<detid_t>>;
 } // namespace Mantid
 
-#endif // MANTID_API_SPECTRADETECTORMAP_TYPES
diff --git a/Framework/API/inc/MantidAPI/SpectrumDetectorMapping.h b/Framework/API/inc/MantidAPI/SpectrumDetectorMapping.h
index 26ecd29a267..3f6847d3f3c 100644
--- a/Framework/API/inc/MantidAPI/SpectrumDetectorMapping.h
+++ b/Framework/API/inc/MantidAPI/SpectrumDetectorMapping.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRUMDETECTORMAPPING_H_
-#define MANTID_API_SPECTRUMDETECTORMAPPING_H_
+#pragma once
 
 #include <set>
 #include <vector>
@@ -67,5 +66,3 @@ private:
 
 } // namespace API
 } // namespace Mantid
-
-#endif /* MANTID_API_SPECTRUMDETECTORMAPPING_H_ */
diff --git a/Framework/API/inc/MantidAPI/SpectrumInfo.h b/Framework/API/inc/MantidAPI/SpectrumInfo.h
index 359b361aa59..926a6c94498 100644
--- a/Framework/API/inc/MantidAPI/SpectrumInfo.h
+++ b/Framework/API/inc/MantidAPI/SpectrumInfo.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRUMINFO_H_
-#define MANTID_API_SPECTRUMINFO_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/SpectrumInfoIterator.h"
@@ -111,4 +110,3 @@ using SpectrumInfoConstIt = SpectrumInfoIterator<const SpectrumInfo>;
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SPECTRUMINFO_H_ */
diff --git a/Framework/API/inc/MantidAPI/SpectrumInfoItem.h b/Framework/API/inc/MantidAPI/SpectrumInfoItem.h
index 29ac3b3c900..a743e1f0116 100644
--- a/Framework/API/inc/MantidAPI/SpectrumInfoItem.h
+++ b/Framework/API/inc/MantidAPI/SpectrumInfoItem.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRUMINFOITEM_H_
-#define MANTID_API_SPECTRUMINFOITEM_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidKernel/V3D.h"
@@ -80,4 +79,3 @@ public:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SPECTRUMINFOITEM_H_ */
diff --git a/Framework/API/inc/MantidAPI/SpectrumInfoIterator.h b/Framework/API/inc/MantidAPI/SpectrumInfoIterator.h
index 6cb8b133be0..f3370579b61 100644
--- a/Framework/API/inc/MantidAPI/SpectrumInfoIterator.h
+++ b/Framework/API/inc/MantidAPI/SpectrumInfoIterator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRUMINFOITERATOR_H_
-#define MANTID_API_SPECTRUMINFOITERATOR_H_
+#pragma once
 
 #include "MantidAPI/SpectrumInfoItem.h"
 #include <boost/iterator/iterator_facade.hpp>
@@ -86,4 +85,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_SPECTRUMINFOITERATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/TableRow.h b/Framework/API/inc/MantidAPI/TableRow.h
index a53f979eaed..f3096148507 100644
--- a/Framework/API/inc/MantidAPI/TableRow.h
+++ b/Framework/API/inc/MantidAPI/TableRow.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_TABLEROW_H_
-#define MANTID_API_TABLEROW_H_
+#pragma once
 
 #include "MantidAPI/Column.h"
 
@@ -170,5 +169,3 @@ MANTID_API_DLL std::ostream &operator<<(std::ostream &s, const TableRow &row);
 
 } // namespace API
 } // namespace Mantid
-
-#endif /*  MANTID_API_TABLEROW_H_ */
diff --git a/Framework/API/inc/MantidAPI/TempFunction.h b/Framework/API/inc/MantidAPI/TempFunction.h
index 1feae331a47..f5c1346a938 100644
--- a/Framework/API/inc/MantidAPI/TempFunction.h
+++ b/Framework/API/inc/MantidAPI/TempFunction.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_TEMPFUNCTION_H_
-#define MANTID_API_TEMPFUNCTION_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -16,7 +15,6 @@
 
 #ifdef _WIN32
 #pragma warning(disable : 4250)
-#endif
 
 namespace Mantid {
 namespace API {
@@ -204,4 +202,4 @@ protected:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_TEMPFUNCTION_H_*/
+ /*MANTID_API_TEMPFUNCTION_H_*/
diff --git a/Framework/API/inc/MantidAPI/TextAxis.h b/Framework/API/inc/MantidAPI/TextAxis.h
index 634aabd2208..b4d3838fe76 100644
--- a/Framework/API/inc/MantidAPI/TextAxis.h
+++ b/Framework/API/inc/MantidAPI/TextAxis.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_TEXTAXIS_H_
-#define MANTID_API_TEXTAXIS_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -69,5 +68,3 @@ private:
 
 } // namespace API
 } // namespace Mantid
-
-#endif /* MANTID_API_TEXTAXIS_H_ */
diff --git a/Framework/API/inc/MantidAPI/TransformScaleFactory.h b/Framework/API/inc/MantidAPI/TransformScaleFactory.h
index 33693f24c7b..a4353cf256a 100644
--- a/Framework/API/inc/MantidAPI/TransformScaleFactory.h
+++ b/Framework/API/inc/MantidAPI/TransformScaleFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_TRANSFORMSCALEFACTORY_H_
-#define MANTID_API_TRANSFORMSCALEFACTORY_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidKernel/DynamicFactory.h"
@@ -64,4 +63,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
 }
 } // namespace Mantid
 
-#endif /* MANTID_API_TRANSFORMSCALEFACTORY_H_ */
diff --git a/Framework/API/inc/MantidAPI/VectorParameter.h b/Framework/API/inc/MantidAPI/VectorParameter.h
index 22734b9e1c7..aa4c69e0e80 100644
--- a/Framework/API/inc/MantidAPI/VectorParameter.h
+++ b/Framework/API/inc/MantidAPI/VectorParameter.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_MDALGORITHMS_VectorParameter_H_
-#define MANTID_MDALGORITHMS_VectorParameter_H_
+#pragma once
 
 #include "MantidAPI/ImplicitFunctionParameter.h"
 #include "MantidKernel/System.h"
@@ -240,4 +239,3 @@ ElemType &VectorParameter<Derived, ElemType>::at(size_t index) {
 } // namespace API
 } // namespace Mantid
 
-#endif
diff --git a/Framework/API/inc/MantidAPI/VectorParameterParser.h b/Framework/API/inc/MantidAPI/VectorParameterParser.h
index d0947fcbfa4..fd158e4153b 100644
--- a/Framework/API/inc/MantidAPI/VectorParameterParser.h
+++ b/Framework/API/inc/MantidAPI/VectorParameterParser.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef VECTOR_VALUE_PARAMETER_PARSER_H_
-#define VECTOR_VALUE_PARAMETER_PARSER_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -132,5 +131,3 @@ void VectorParameterParser<VectorValueParameterType>::setSuccessorParser(
 }
 } // namespace API
 } // namespace Mantid
-
-#endif
diff --git a/Framework/API/inc/MantidAPI/Workspace.h b/Framework/API/inc/MantidAPI/Workspace.h
index af1a968a2ce..d4bafe889ef 100644
--- a/Framework/API/inc/MantidAPI/Workspace.h
+++ b/Framework/API/inc/MantidAPI/Workspace.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACE_H_
-#define MANTID_API_WORKSPACE_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/Workspace_fwd.h"
@@ -118,4 +117,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_WORKSPACE_H_*/
diff --git a/Framework/API/inc/MantidAPI/WorkspaceFactory.h b/Framework/API/inc/MantidAPI/WorkspaceFactory.h
index b3847501f74..b8e2719ed89 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceFactory.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceFactory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_KERNEL_WORKSPACEFACTORY_H_
-#define MANTID_KERNEL_WORKSPACEFACTORY_H_
+#pragma once
 
 /* Used to register classes into the factory. creates a global object in an
  * anonymous namespace. The object itself does nothing, but the comma operator
@@ -98,5 +97,3 @@ EXTERN_MANTID_API template class MANTID_API_DLL
     Mantid::Kernel::SingletonHolder<Mantid::API::WorkspaceFactoryImpl>;
 }
 } // namespace Mantid
-
-#endif /*MANTID_KERNEL_WORKSPACEFACTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/WorkspaceGroup.h b/Framework/API/inc/MantidAPI/WorkspaceGroup.h
index c10e7fa5953..bc63d5e9b59 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceGroup.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceGroup.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACEGROUP_H
-#define MANTID_API_WORKSPACEGROUP_H
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -170,4 +169,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_WORKSPACEGROUP_H*/
diff --git a/Framework/API/inc/MantidAPI/WorkspaceGroup_fwd.h b/Framework/API/inc/MantidAPI/WorkspaceGroup_fwd.h
index f435fd36314..e70645159a4 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceGroup_fwd.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceGroup_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACEGROUP_FWD_H_
-#define MANTID_API_WORKSPACEGROUP_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -30,4 +29,3 @@ using WorkspaceGroup_const_uptr = std::unique_ptr<const WorkspaceGroup>;
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_WORKSPACEGROUP_FWD_H_
diff --git a/Framework/API/inc/MantidAPI/WorkspaceHasDxValidator.h b/Framework/API/inc/MantidAPI/WorkspaceHasDxValidator.h
index e1d9570ac26..a69bff49ef0 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceHasDxValidator.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceHasDxValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACEHASDXVALIDATOR_H_
-#define MANTID_API_WORKSPACEHASDXVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 
@@ -29,4 +28,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_WORKSPACEHASDXVALIDATOR_H_ */
diff --git a/Framework/API/inc/MantidAPI/WorkspaceHistory.h b/Framework/API/inc/MantidAPI/WorkspaceHistory.h
index 285feb58fe9..c86c8e34c28 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceHistory.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceHistory.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACEHISTORY_H_
-#define MANTID_API_WORKSPACEHISTORY_H_
+#pragma once
 
 //----------------------------------------------------------------------
 // Includes
@@ -99,4 +98,3 @@ MANTID_API_DLL std::ostream &operator<<(std::ostream &,
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_WORKSPACEHISTORY_H_*/
diff --git a/Framework/API/inc/MantidAPI/WorkspaceNearestNeighbourInfo.h b/Framework/API/inc/MantidAPI/WorkspaceNearestNeighbourInfo.h
index 78f48732827..9c8aaa2c1e4 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceNearestNeighbourInfo.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceNearestNeighbourInfo.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_NEARESTNEIGHBOURINFO_H_
-#define MANTID_API_NEARESTNEIGHBOURINFO_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidGeometry/IDTypes.h"
@@ -48,4 +47,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_WORKSPACENEARESTNEIGHBOURINFO_H_ */
diff --git a/Framework/API/inc/MantidAPI/WorkspaceNearestNeighbours.h b/Framework/API/inc/MantidAPI/WorkspaceNearestNeighbours.h
index 7a9e8980c41..5d45c963666 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceNearestNeighbours.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceNearestNeighbours.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_GEOMETRY_INSTRUMENT_NEARESTNEIGHBOURS
-#define MANTID_GEOMETRY_INSTRUMENT_NEARESTNEIGHBOURS
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidGeometry/IDTypes.h"
@@ -107,5 +106,3 @@ private:
 
 } // namespace API
 } // namespace Mantid
-
-#endif
diff --git a/Framework/API/inc/MantidAPI/WorkspaceOpOverloads.h b/Framework/API/inc/MantidAPI/WorkspaceOpOverloads.h
index 74d8afe4599..7cd63ae38c6 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceOpOverloads.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceOpOverloads.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKOPOVERLOADS_H_
-#define MANTID_API_WORKOPOVERLOADS_H_
+#pragma once
 
 #include "MantidAPI/DllConfig.h"
 #include "MantidAPI/MatrixWorkspace_fwd.h"
@@ -91,4 +90,3 @@ struct MANTID_API_DLL WorkspaceHelpers {
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_WORKOPOVERLOADS_H_ */
diff --git a/Framework/API/inc/MantidAPI/WorkspaceProperty.h b/Framework/API/inc/MantidAPI/WorkspaceProperty.h
index f0eba3cd9fa..9c720ac85f2 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceProperty.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceProperty.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACEPROPERTY_H_
-#define MANTID_API_WORKSPACEPROPERTY_H_
+#pragma once
 
 #include "MantidAPI/IWorkspaceProperty.h"
 #include "MantidKernel/Logger.h"
@@ -152,4 +151,3 @@ Kernel::Logger WorkspaceProperty<TYPE>::g_log("WorkspaceProperty");
 } // namespace API
 } // namespace Mantid
 
-#endif /*MANTID_API_WORKSPACEPROPERTY_H_*/
diff --git a/Framework/API/inc/MantidAPI/WorkspaceUnitValidator.h b/Framework/API/inc/MantidAPI/WorkspaceUnitValidator.h
index 94966027bb7..70562a83408 100644
--- a/Framework/API/inc/MantidAPI/WorkspaceUnitValidator.h
+++ b/Framework/API/inc/MantidAPI/WorkspaceUnitValidator.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACEUNITVALIDATOR_H_
-#define MANTID_API_WORKSPACEUNITVALIDATOR_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceValidator.h"
 
@@ -35,4 +34,3 @@ private:
 } // namespace API
 } // namespace Mantid
 
-#endif /* MANTID_API_WORKSPACEUNITVALIDATOR_H_ */
\ No newline at end of file
diff --git a/Framework/API/inc/MantidAPI/Workspace_fwd.h b/Framework/API/inc/MantidAPI/Workspace_fwd.h
index 846b023591c..d449fc82bdc 100644
--- a/Framework/API/inc/MantidAPI/Workspace_fwd.h
+++ b/Framework/API/inc/MantidAPI/Workspace_fwd.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACE_FWD_H_
-#define MANTID_API_WORKSPACE_FWD_H_
+#pragma once
 
 #include <boost/shared_ptr.hpp>
 #include <memory>
@@ -30,4 +29,3 @@ using Workspace_const_uptr = std::unique_ptr<const Workspace>;
 } // namespace API
 } // namespace Mantid
 
-#endif // MANTID_API_WORKSPACE_FWD_H_
diff --git a/Framework/API/test/ADSValidatorTest.h b/Framework/API/test/ADSValidatorTest.h
index 2300185625a..f18f1ccdc57 100644
--- a/Framework/API/test/ADSValidatorTest.h
+++ b/Framework/API/test/ADSValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ADSVALIDATORTEST_H_
-#define MANTID_API_ADSVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -129,4 +128,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_ADSVALIDATORTEST_H_ */
diff --git a/Framework/API/test/AlgorithmFactoryObserverTest.h b/Framework/API/test/AlgorithmFactoryObserverTest.h
index 8bbda51dfd6..614e23e466b 100644
--- a/Framework/API/test/AlgorithmFactoryObserverTest.h
+++ b/Framework/API/test/AlgorithmFactoryObserverTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef ALGORITHMFACTORYOBSERVERTEST_H_
-#define ALGORITHMFACTORYOBSERVERTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -81,4 +80,3 @@ public:
   }
 };
 
-#endif /* ALGORITHMFACTORYOBSERVERTEST_H_ */
\ No newline at end of file
diff --git a/Framework/API/test/AlgorithmFactoryTest.h b/Framework/API/test/AlgorithmFactoryTest.h
index 0e12c7d1670..11f6ebee7b8 100644
--- a/Framework/API/test/AlgorithmFactoryTest.h
+++ b/Framework/API/test/AlgorithmFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef ALGORITHMFACTORYTEST_H_
-#define ALGORITHMFACTORYTEST_H_
+#pragma once
 
 #include "FakeAlgorithms.h"
 #include "MantidAPI/AlgorithmFactory.h"
@@ -244,4 +243,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/AlgorithmHasPropertyTest.h b/Framework/API/test/AlgorithmHasPropertyTest.h
index 266e5bf281a..5a1ebbccc19 100644
--- a/Framework/API/test/AlgorithmHasPropertyTest.h
+++ b/Framework/API/test/AlgorithmHasPropertyTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHMHASPROPERTYTEST_H_
-#define MANTID_API_ALGORITHMHASPROPERTYTEST_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/AlgorithmHasProperty.h"
@@ -90,4 +89,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_ALGORITHMHASPROPERTY_H_ */
diff --git a/Framework/API/test/AlgorithmHistoryTest.h b/Framework/API/test/AlgorithmHistoryTest.h
index 69d391a3554..2dffd446ae5 100644
--- a/Framework/API/test/AlgorithmHistoryTest.h
+++ b/Framework/API/test/AlgorithmHistoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef ALGORITHMHISTORYTEST_H_
-#define ALGORITHMHISTORYTEST_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/AlgorithmHistory.h"
@@ -254,4 +253,3 @@ private:
   size_t m_execCount;
 };
 
-#endif /* ALGORITHMHISTORYTEST_H_*/
diff --git a/Framework/API/test/AlgorithmMPITest.h b/Framework/API/test/AlgorithmMPITest.h
index 67c5f5e271e..642ae00cd42 100644
--- a/Framework/API/test/AlgorithmMPITest.h
+++ b/Framework/API/test/AlgorithmMPITest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef ALGORITHMMPITEST_H_
-#define ALGORITHMMPITEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -488,4 +487,3 @@ public:
   }
 };
 
-#endif /*ALGORITHMMPITEST_H_*/
diff --git a/Framework/API/test/AlgorithmManagerTest.h b/Framework/API/test/AlgorithmManagerTest.h
index 3504b241881..f5ea83e4ad9 100644
--- a/Framework/API/test/AlgorithmManagerTest.h
+++ b/Framework/API/test/AlgorithmManagerTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef AlgorithmManagerTest_H_
-#define AlgorithmManagerTest_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -404,4 +403,3 @@ public:
   int m_notificationValue;
 };
 
-#endif /* AlgorithmManagerTest_H_*/
diff --git a/Framework/API/test/AlgorithmPropertyTest.h b/Framework/API/test/AlgorithmPropertyTest.h
index 3cdb1c31c76..7addc9104c3 100644
--- a/Framework/API/test/AlgorithmPropertyTest.h
+++ b/Framework/API/test/AlgorithmPropertyTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ALGORITHMPROPERTYTEST_H_
-#define MANTID_API_ALGORITHMPROPERTYTEST_H_
+#pragma once
 
 #include "MantidKernel/System.h"
 #include "MantidKernel/Timer.h"
@@ -216,4 +215,3 @@ private:
   }
 };
 
-#endif /* MANTID_API_ALGORITHMPROPERTYTEST_H_ */
diff --git a/Framework/API/test/AlgorithmProxyTest.h b/Framework/API/test/AlgorithmProxyTest.h
index e30baa8ef14..4d01de0fc38 100644
--- a/Framework/API/test/AlgorithmProxyTest.h
+++ b/Framework/API/test/AlgorithmProxyTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef ALGORITHMPROXYTEST_H_
-#define ALGORITHMPROXYTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -260,4 +259,3 @@ public:
   }
 };
 
-#endif /*ALGORITHMPROXYTEST_H_*/
diff --git a/Framework/API/test/AlgorithmTest.h b/Framework/API/test/AlgorithmTest.h
index e2bf699ff8e..33f4137b1cb 100644
--- a/Framework/API/test/AlgorithmTest.h
+++ b/Framework/API/test/AlgorithmTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef ALGORITHMTEST_H_
-#define ALGORITHMTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -1023,4 +1022,3 @@ private:
   MatrixWorkspace_sptr ws3;
 };
 
-#endif /*ALGORITHMTEST_H_*/
diff --git a/Framework/API/test/AnalysisDataServiceObserverTest.h b/Framework/API/test/AnalysisDataServiceObserverTest.h
index c16b3ff1e75..6d6fbd2a121 100644
--- a/Framework/API/test/AnalysisDataServiceObserverTest.h
+++ b/Framework/API/test/AnalysisDataServiceObserverTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef ANALYSISDATASERVICEOBSERVERTEST_H_
-#define ANALYSISDATASERVICEOBSERVERTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -240,4 +239,3 @@ public:
   }
 };
 
-#endif /* ANALYSISDATASERVICEOBSERVERTEST_H_ */
\ No newline at end of file
diff --git a/Framework/API/test/AnalysisDataServiceTest.h b/Framework/API/test/AnalysisDataServiceTest.h
index c906d5b1b80..2ea3bd951d7 100644
--- a/Framework/API/test/AnalysisDataServiceTest.h
+++ b/Framework/API/test/AnalysisDataServiceTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef ANALYSISDATASERVICETEST_H_
-#define ANALYSISDATASERVICETEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -606,4 +605,3 @@ private:
   }
 };
 
-#endif /*ANALYSISDATASERVICETEST_H_*/
diff --git a/Framework/API/test/AsynchronousTest.h b/Framework/API/test/AsynchronousTest.h
index e42e6cb10ad..6d84137b0c0 100644
--- a/Framework/API/test/AsynchronousTest.h
+++ b/Framework/API/test/AsynchronousTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef ASYNCHRONOUSTEST_H_
-#define ASYNCHRONOUSTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -295,4 +294,3 @@ std::mutex AsynchronousTest::g_mtx;
 bool AsynchronousTest::g_testStarted = false;
 bool AsynchronousTest::g_execStarted = false;
 
-#endif /*ASYNCHRONOUSTEST_H_*/
diff --git a/Framework/API/test/BinEdgeAxisTest.h b/Framework/API/test/BinEdgeAxisTest.h
index 60b583c0edf..e32d4927809 100644
--- a/Framework/API/test/BinEdgeAxisTest.h
+++ b/Framework/API/test/BinEdgeAxisTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_BINEDGEAXISTEST_H_
-#define MANTID_API_BINEDGEAXISTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -82,4 +81,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_BINEDGEAXISTEST_H_ */
diff --git a/Framework/API/test/BoxControllerTest.h b/Framework/API/test/BoxControllerTest.h
index 6f8245e75bb..77add59d733 100644
--- a/Framework/API/test/BoxControllerTest.h
+++ b/Framework/API/test/BoxControllerTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef BOXPLITCONTROLLER_TEST_H
-#define BOXPLITCONTROLLER_TEST_H
+#pragma once
 
 #include "MantidAPI/BoxController.h"
 #include "MantidAPI/IBoxControllerIO.h"
@@ -397,4 +396,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/CitationTest.h b/Framework/API/test/CitationTest.h
index 9b628be1aa8..7b6db6d6128 100644
--- a/Framework/API/test/CitationTest.h
+++ b/Framework/API/test/CitationTest.h
@@ -5,8 +5,7 @@
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
 
-#ifndef CITATIONTEST_H_
-#define CITATIONTEST_H_
+#pragma once
 
 #include "MantidAPI/Citation.h"
 #include "MantidTestHelpers/NexusTestHelper.h"
@@ -120,4 +119,3 @@ public:
   }
 };
 
-#endif /* CITATIONTEST_H_ */
\ No newline at end of file
diff --git a/Framework/API/test/CommonBinsValidatorTest.h b/Framework/API/test/CommonBinsValidatorTest.h
index 18222c77fc9..7190a0beb10 100644
--- a/Framework/API/test/CommonBinsValidatorTest.h
+++ b/Framework/API/test/CommonBinsValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_COMMONBINSVALIDATORTEST_H_
-#define MANTID_API_COMMONBINSVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -63,4 +62,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_COMMONBINSVALIDATORTEST_H_ */
diff --git a/Framework/API/test/CompositeFunctionTest.h b/Framework/API/test/CompositeFunctionTest.h
index d325cb2a67e..c6c664f2fc2 100644
--- a/Framework/API/test/CompositeFunctionTest.h
+++ b/Framework/API/test/CompositeFunctionTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef COMPOSITEFUNCTIONTEST_H_
-#define COMPOSITEFUNCTIONTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -1247,4 +1246,3 @@ public:
   }
 };
 
-#endif /*COMPOSITEFUNCTIONTEST_H_*/
diff --git a/Framework/API/test/CoordTransformTest.h b/Framework/API/test/CoordTransformTest.h
index f1c481a9791..eb355e82233 100644
--- a/Framework/API/test/CoordTransformTest.h
+++ b/Framework/API/test/CoordTransformTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_MDEVENTS_COORDTRANSFORMTEST_H_
-#define MANTID_MDEVENTS_COORDTRANSFORMTEST_H_
+#pragma once
 
 #include "MantidAPI/CoordTransform.h"
 #include "MantidKernel/System.h"
@@ -21,4 +20,3 @@ public:
   }
 };
 
-#endif /* MANTID_MDEVENTS_COORDTRANSFORMTEST_H_ */
diff --git a/Framework/API/test/CostFunctionFactoryTest.h b/Framework/API/test/CostFunctionFactoryTest.h
index c49c7657156..dcdfa7a90d1 100644
--- a/Framework/API/test/CostFunctionFactoryTest.h
+++ b/Framework/API/test/CostFunctionFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef COSTFUNCTIONFACTORYTEST_H_
-#define COSTFUNCTIONFACTORYTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -58,4 +57,3 @@ public:
   }
 };
 
-#endif /*COSTFUNCTIONFACTORYTEST_H_*/
diff --git a/Framework/API/test/DataProcessorAlgorithmTest.h b/Framework/API/test/DataProcessorAlgorithmTest.h
index 0a49f39dac4..db6c958cf21 100644
--- a/Framework/API/test/DataProcessorAlgorithmTest.h
+++ b/Framework/API/test/DataProcessorAlgorithmTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_DATAPROCESSORALGORITHMTEST_H_
-#define MANTID_API_DATAPROCESSORALGORITHMTEST_H_
+#pragma once
 
 #include "MantidAPI/AnalysisDataService.h"
 #include "MantidAPI/DataProcessorAlgorithm.h"
@@ -252,4 +251,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_DATAPROCESSORALGORITHMTEST_H_ */
diff --git a/Framework/API/test/DetectorInfoTest.h b/Framework/API/test/DetectorInfoTest.h
index 1c08d29e3ef..abe01d11665 100644
--- a/Framework/API/test/DetectorInfoTest.h
+++ b/Framework/API/test/DetectorInfoTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_GEOMETRY_DETECTORINFOTEST_H_
-#define MANTID_GEOMETRY_DETECTORINFOTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -563,4 +562,3 @@ private:
   WorkspaceTester m_workspace;
 };
 
-#endif /* MANTID_GEOMETRY_DETECTORINFOTEST_H_ */
diff --git a/Framework/API/test/DetectorSearcherTest.h b/Framework/API/test/DetectorSearcherTest.h
index 7ade5ab4ed3..5671cfed6fc 100644
--- a/Framework/API/test/DetectorSearcherTest.h
+++ b/Framework/API/test/DetectorSearcherTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_DETECTORSEARCHERTEST_H_
-#define MANTID_API_DETECTORSEARCHERTEST_H_
+#pragma once
 
 #include "MantidAPI/DetectorSearcher.h"
 #include "MantidAPI/ExperimentInfo.h"
@@ -237,4 +236,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/EnabledWhenWorkspaceIsTypeTest.h b/Framework/API/test/EnabledWhenWorkspaceIsTypeTest.h
index 88e061858e3..85edade9db1 100644
--- a/Framework/API/test/EnabledWhenWorkspaceIsTypeTest.h
+++ b/Framework/API/test/EnabledWhenWorkspaceIsTypeTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ENABLEDWHENWORKSPACEISTYPETEST_H_
-#define MANTID_API_ENABLEDWHENWORKSPACEISTYPETEST_H_
+#pragma once
 
 #include "MantidKernel/System.h"
 #include "MantidKernel/Timer.h"
@@ -91,4 +90,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_ENABLEDWHENWORKSPACEISTYPETEST_H_ */
diff --git a/Framework/API/test/EqualBinSizesValidatorTest.h b/Framework/API/test/EqualBinSizesValidatorTest.h
index 5848c90b6cc..a03616cfcc0 100644
--- a/Framework/API/test/EqualBinSizesValidatorTest.h
+++ b/Framework/API/test/EqualBinSizesValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_EQUALBINSIZESVALIDATORTEST_H_
-#define MANTID_API_EQUALBINSIZESVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -67,4 +66,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_EQUALBINSIZESVALIDATORTEST_H_ */
diff --git a/Framework/API/test/ExperimentInfoTest.h b/Framework/API/test/ExperimentInfoTest.h
index b85cfc85c29..a53c70b0f4b 100644
--- a/Framework/API/test/ExperimentInfoTest.h
+++ b/Framework/API/test/ExperimentInfoTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_EXPERIMENTINFOTEST_H_
-#define MANTID_API_EXPERIMENTINFOTEST_H_
+#pragma once
 
 #include "MantidAPI/ExperimentInfo.h"
 #include "MantidAPI/Run.h"
@@ -950,4 +949,3 @@ public:
     m_provisionedInstrument->getBoundingBox(box);
   }
 };
-#endif /* MANTID_API_EXPERIMENTINFOTEST_H_ */
diff --git a/Framework/API/test/ExpressionTest.h b/Framework/API/test/ExpressionTest.h
index 68db7b49d28..6b8ea0f70d3 100644
--- a/Framework/API/test/ExpressionTest.h
+++ b/Framework/API/test/ExpressionTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef EXPRESSIONTEST_H_
-#define EXPRESSIONTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -547,4 +546,3 @@ public:
   }
 };
 
-#endif /*EXPRESSIONTEST_H_*/
diff --git a/Framework/API/test/FakeAlgorithms.h b/Framework/API/test/FakeAlgorithms.h
index 0795367a341..62eb4e9217e 100644
--- a/Framework/API/test/FakeAlgorithms.h
+++ b/Framework/API/test/FakeAlgorithms.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FAKEALGORITHMS_H_
-#define FAKEALGORITHMS_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidKernel/ArrayProperty.h"
@@ -119,4 +118,3 @@ public:
   }
   void exec() override {}
 };
-#endif
diff --git a/Framework/API/test/FileBackedExperimentInfoTest.h b/Framework/API/test/FileBackedExperimentInfoTest.h
index 7765b7aec7f..8dca79f4373 100644
--- a/Framework/API/test/FileBackedExperimentInfoTest.h
+++ b/Framework/API/test/FileBackedExperimentInfoTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_FILEBACKEDEXPERIMENTINFOTEST_H_
-#define MANTID_API_FILEBACKEDEXPERIMENTINFOTEST_H_
+#pragma once
 
 #include "ExperimentInfoTest.h"
 #include "MantidAPI/FileBackedExperimentInfo.h"
@@ -172,4 +171,3 @@ private:
   std::string m_filename;
 };
 
-#endif /* MANTID_API_FILEBACKEDEXPERIMENTINFOTEST_H_ */
diff --git a/Framework/API/test/FileFinderTest.h b/Framework/API/test/FileFinderTest.h
index b94cf7e80ef..cd4ed2d19c2 100644
--- a/Framework/API/test/FileFinderTest.h
+++ b/Framework/API/test/FileFinderTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FILEFINDERTEST_H_
-#define FILEFINDERTEST_H_
+#pragma once
 
 #include "MantidAPI/FileFinder.h"
 #include "MantidKernel/ConfigService.h"
@@ -471,7 +470,6 @@ public:
     TS_ASSERT(path.find("CSp78173.Raw") != std::string::npos);
 #else
     TS_ASSERT(path.find("CSP78173.raw") != std::string::npos);
-#endif
     Poco::File file(path);
     TS_ASSERT(file.exists());
     std::string path2 =
@@ -509,7 +507,6 @@ public:
     TS_ASSERT_THROWS_ANYTHING(fileOn2.exists());
     TS_ASSERT_THROWS_ANYTHING(fileOn3.exists());
     TS_ASSERT_THROWS_ANYTHING(fileOn4.exists());
-#endif
 
     fileFinder.setCaseSensitive(startingCaseOption);
   }
@@ -676,4 +673,4 @@ private:
   size_t m_filesToFind;
 };
 
-#endif /*FILEFINDERTEST_H_*/
+ /*FILEFINDERTEST_H_*/
diff --git a/Framework/API/test/FilePropertyTest.h b/Framework/API/test/FilePropertyTest.h
index 15e68d6f96c..59fdec87d6c 100644
--- a/Framework/API/test/FilePropertyTest.h
+++ b/Framework/API/test/FilePropertyTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FILEPROPERTYTEST_H_
-#define FILEPROPERTYTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -244,4 +243,3 @@ private:
   }
 };
 
-#endif
diff --git a/Framework/API/test/FrameworkManagerTest.h b/Framework/API/test/FrameworkManagerTest.h
index a76b34f7dc7..d9e87e3e991 100644
--- a/Framework/API/test/FrameworkManagerTest.h
+++ b/Framework/API/test/FrameworkManagerTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FRAMEWORKMANAGERTEST_H_
-#define FRAMEWORKMANAGERTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -53,7 +52,6 @@ public:
   // Make sure FrameworkManager is always instantiated. This is needed to
   // initialize the MPI environment.
   FrameworkManagerTest() { FrameworkManager::Instance(); }
-#endif
 
   void testConstructor() {
     // Not really much to test
@@ -63,7 +61,6 @@ public:
     // If this is 'MPI Mantid' then test that the mpi environment has been
     // initialized
     TS_ASSERT(boost::mpi::environment::initialized());
-#endif
   }
 
   void testcreateAlgorithm() {
@@ -101,4 +98,4 @@ public:
   }
 };
 
-#endif /*FRAMEWORKMANAGERTEST_H_*/
+ /*FRAMEWORKMANAGERTEST_H_*/
diff --git a/Framework/API/test/FuncMinimizerFactoryTest.h b/Framework/API/test/FuncMinimizerFactoryTest.h
index 583e90cac27..4ae69055224 100644
--- a/Framework/API/test/FuncMinimizerFactoryTest.h
+++ b/Framework/API/test/FuncMinimizerFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FUNCMINIMIZERFACTORYTEST_H_
-#define FUNCMINIMIZERFACTORYTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -93,4 +92,3 @@ public:
   }
 };
 
-#endif /*FUNCMINIMIZERFACTORYTEST_H_*/
diff --git a/Framework/API/test/FunctionAttributeTest.h b/Framework/API/test/FunctionAttributeTest.h
index 5b47668af33..be522ad9ed1 100644
--- a/Framework/API/test/FunctionAttributeTest.h
+++ b/Framework/API/test/FunctionAttributeTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FUNCTIONATTRIBUTETEST_H_
-#define FUNCTIONATTRIBUTETEST_H_
+#pragma once
 
 #include "MantidAPI/AnalysisDataService.h"
 #include "MantidAPI/FunctionFactory.h"
@@ -268,4 +267,3 @@ public:
   }
 };
 
-#endif /* FUNCTIONATTRIBUTETEST_H_ */
diff --git a/Framework/API/test/FunctionDomainGeneralTest.h b/Framework/API/test/FunctionDomainGeneralTest.h
index f3178a80e9a..cedcaa0e530 100644
--- a/Framework/API/test/FunctionDomainGeneralTest.h
+++ b/Framework/API/test/FunctionDomainGeneralTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FUNCTIONDOMAINGENERALTEST_H_
-#define FUNCTIONDOMAINGENERALTEST_H_
+#pragma once
 
 #include "MantidAPI/Column.h"
 #include "MantidAPI/FunctionDomainGeneral.h"
@@ -114,4 +113,3 @@ public:
   }
 };
 
-#endif /*FUNCTIONDOMAINGENERALTEST_H_*/
diff --git a/Framework/API/test/FunctionDomainTest.h b/Framework/API/test/FunctionDomainTest.h
index f1d144942b5..0a7d1b06174 100644
--- a/Framework/API/test/FunctionDomainTest.h
+++ b/Framework/API/test/FunctionDomainTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FUNCTIONDOMAINTEST_H_
-#define FUNCTIONDOMAINTEST_H_
+#pragma once
 
 #include "MantidAPI/FunctionDomain1D.h"
 #include "MantidAPI/MatrixWorkspace.h"
@@ -83,4 +82,3 @@ private:
   std::vector<double> data;
 };
 
-#endif /*FUNCTIONDOMAINTEST_H_*/
diff --git a/Framework/API/test/FunctionFactoryTest.h b/Framework/API/test/FunctionFactoryTest.h
index 10222ca650f..954ffffab9a 100644
--- a/Framework/API/test/FunctionFactoryTest.h
+++ b/Framework/API/test/FunctionFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FUNCTIONFACTORYTEST_H_
-#define FUNCTIONFACTORYTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -513,4 +512,3 @@ public:
   }
 };
 
-#endif /*FUNCTIONFACTORYTEST_H_*/
diff --git a/Framework/API/test/FunctionParameterDecoratorTest.h b/Framework/API/test/FunctionParameterDecoratorTest.h
index 4c831f6f1b5..6f70f2f9efa 100644
--- a/Framework/API/test/FunctionParameterDecoratorTest.h
+++ b/Framework/API/test/FunctionParameterDecoratorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WRAPPEDFUNCTIONTEST_H_
-#define MANTID_API_WRAPPEDFUNCTIONTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -460,4 +459,3 @@ private:
   };
 };
 
-#endif /* MANTID_API_WRAPPEDFUNCTIONTEST_H_ */
diff --git a/Framework/API/test/FunctionPropertyTest.h b/Framework/API/test/FunctionPropertyTest.h
index a3b26260c1f..d7ab77c24c8 100644
--- a/Framework/API/test/FunctionPropertyTest.h
+++ b/Framework/API/test/FunctionPropertyTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FUNCTIONPROPERTYTEST_H_
-#define FUNCTIONPROPERTYTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -127,4 +126,3 @@ private:
   }
 };
 
-#endif /*FUNCTIONPROPERTYTEST_H_*/
diff --git a/Framework/API/test/FunctionTest.h b/Framework/API/test/FunctionTest.h
index 4383397c8a2..1ebc983ea4d 100644
--- a/Framework/API/test/FunctionTest.h
+++ b/Framework/API/test/FunctionTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IFUNCTIONTEST_H_
-#define IFUNCTIONTEST_H_
+#pragma once
 
 #include "MantidAPI/AnalysisDataService.h"
 #include "MantidAPI/FrameworkManager.h"
@@ -489,4 +488,3 @@ public:
   //}
 };
 
-#endif /*IFUNCTIONTEST_H_*/
diff --git a/Framework/API/test/FunctionValuesTest.h b/Framework/API/test/FunctionValuesTest.h
index efb8f8ec64e..b67258aa494 100644
--- a/Framework/API/test/FunctionValuesTest.h
+++ b/Framework/API/test/FunctionValuesTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef FUNCTIONVALUESTEST_H_
-#define FUNCTIONVALUESTEST_H_
+#pragma once
 
 #include "MantidAPI/FunctionDomain1D.h"
 #include "MantidAPI/FunctionValues.h"
@@ -128,4 +127,3 @@ private:
   std::vector<double> x;
 };
 
-#endif /*FUNCTIONVALUESTEST_H_*/
diff --git a/Framework/API/test/GroupingLoaderTest.h b/Framework/API/test/GroupingLoaderTest.h
index 42da85b5043..3d30c8de764 100644
--- a/Framework/API/test/GroupingLoaderTest.h
+++ b/Framework/API/test/GroupingLoaderTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_GROUPINGLOADERTEST_H_
-#define MANTID_API_GROUPINGLOADERTEST_H_
+#pragma once
 
 #include "MantidAPI/FrameworkManager.h"
 #include "MantidAPI/GroupingLoader.h"
@@ -82,4 +81,3 @@ private:
   std::string m_tmpDir;
 };
 
-#endif /* MANTID_API_GROUPINGLOADERTEST_H_ */
diff --git a/Framework/API/test/HistogramValidatorTest.h b/Framework/API/test/HistogramValidatorTest.h
index f41ae19e76d..ff1b39bf9e6 100644
--- a/Framework/API/test/HistogramValidatorTest.h
+++ b/Framework/API/test/HistogramValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_HISTOGRAMVALIDATORTEST_H_
-#define MANTID_API_HISTOGRAMVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -39,4 +38,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_HISTOGRAMVALIDATORTEST_H_ */
diff --git a/Framework/API/test/HistoryItemTest.h b/Framework/API/test/HistoryItemTest.h
index 1d740a141e2..0e0c6fad6b5 100644
--- a/Framework/API/test/HistoryItemTest.h
+++ b/Framework/API/test/HistoryItemTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef HISTORYITEMTEST_H_
-#define HISTORYITEMTEST_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/HistoryView.h"
@@ -34,4 +33,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/HistoryViewTest.h b/Framework/API/test/HistoryViewTest.h
index d828aab4a0b..fbf84c5005a 100644
--- a/Framework/API/test/HistoryViewTest.h
+++ b/Framework/API/test/HistoryViewTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef HISTORYVIEWTEST_H_
-#define HISTORYVIEWTEST_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/HistoryView.h"
@@ -357,4 +356,3 @@ public:
   size_t m_execCount;
 };
 
-#endif
diff --git a/Framework/API/test/IEventListTest.h b/Framework/API/test/IEventListTest.h
index d7c59173d0e..74a45fba63b 100644
--- a/Framework/API/test/IEventListTest.h
+++ b/Framework/API/test/IEventListTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IEVENTLISTTEST_H_
-#define MANTID_API_IEVENTLISTTEST_H_
+#pragma once
 
 #include "MantidKernel/System.h"
 #include "MantidKernel/Timer.h"
@@ -20,4 +19,3 @@ public:
   void test_Something() {}
 };
 
-#endif /* MANTID_API_IEVENTLISTTEST_H_ */
diff --git a/Framework/API/test/IFunction1DSpectrumTest.h b/Framework/API/test/IFunction1DSpectrumTest.h
index bf71a3cf61e..f4ff7c42c55 100644
--- a/Framework/API/test/IFunction1DSpectrumTest.h
+++ b/Framework/API/test/IFunction1DSpectrumTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFUNCTION1DSPECTRUMTEST_H_
-#define MANTID_API_IFUNCTION1DSPECTRUMTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -80,4 +79,3 @@ private:
   };
 };
 
-#endif /* MANTID_API_IFUNCTION1DSPECTRUMTEST_H_ */
diff --git a/Framework/API/test/IFunction1DTest.h b/Framework/API/test/IFunction1DTest.h
index 026978df536..e390237b276 100644
--- a/Framework/API/test/IFunction1DTest.h
+++ b/Framework/API/test/IFunction1DTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IFUNCTION1DTEST_H_
-#define IFUNCTION1DTEST_H_
+#pragma once
 
 #include "MantidAPI/FunctionDomain1D.h"
 #include "MantidAPI/FunctionValues.h"
@@ -82,4 +81,3 @@ public:
   }
 };
 
-#endif /*IFUNCTION1DTEST_H_*/
diff --git a/Framework/API/test/IFunctionMDTest.h b/Framework/API/test/IFunctionMDTest.h
index 161e6de4e63..5778c8cb7af 100644
--- a/Framework/API/test/IFunctionMDTest.h
+++ b/Framework/API/test/IFunctionMDTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IFUNCTIONMDTEST_H_
-#define IFUNCTIONMDTEST_H_
+#pragma once
 
 #include "MantidAPI/IFunctionMD.h"
 #include <cxxtest/TestSuite.h>
@@ -35,4 +34,3 @@ public:
   }
 };
 
-#endif /*IFUNCTIONMDTEST_H_*/
diff --git a/Framework/API/test/IFunctionTest.h b/Framework/API/test/IFunctionTest.h
index 3c723b82c8a..54c35e646c8 100644
--- a/Framework/API/test/IFunctionTest.h
+++ b/Framework/API/test/IFunctionTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_IFUNCTIONTEST_H_
-#define MANTID_API_IFUNCTIONTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -146,4 +145,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_IFUNCTIONTEST_H_*/
diff --git a/Framework/API/test/ILatticeFunctionTest.h b/Framework/API/test/ILatticeFunctionTest.h
index e61113188a0..326a50e1bda 100644
--- a/Framework/API/test/ILatticeFunctionTest.h
+++ b/Framework/API/test/ILatticeFunctionTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ILATTICEFUNCTIONTEST_H_
-#define MANTID_API_ILATTICEFUNCTIONTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 #include <gmock/gmock.h>
@@ -113,4 +112,3 @@ private:
 
 GNU_DIAG_ON_SUGGEST_OVERRIDE
 
-#endif /* MANTID_API_ILATTICEFUNCTIONTEST_H_ */
diff --git a/Framework/API/test/IMDWorkspaceTest.h b/Framework/API/test/IMDWorkspaceTest.h
index de32c35f3cc..2201079f281 100644
--- a/Framework/API/test/IMDWorkspaceTest.h
+++ b/Framework/API/test/IMDWorkspaceTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMD_MATRIX_WORKSPACETEST_H_
-#define IMD_MATRIX_WORKSPACETEST_H_
+#pragma once
 
 // Tests the MatrixWorkspace as an IMDWorkspace.
 
@@ -149,4 +148,3 @@ public:
   }
 };
 
-#endif /*IMD_MATRIX_WORKSPACETEST_H_*/
diff --git a/Framework/API/test/ISpectrumTest.h b/Framework/API/test/ISpectrumTest.h
index 241e1b7867c..67cfad492f6 100644
--- a/Framework/API/test/ISpectrumTest.h
+++ b/Framework/API/test/ISpectrumTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_ISPECTRUMTEST_H_
-#define MANTID_API_ISPECTRUMTEST_H_
+#pragma once
 
 #include "MantidKernel/System.h"
 #include "MantidKernel/Timer.h"
@@ -128,4 +127,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_ISPECTRUMTEST_H_ */
diff --git a/Framework/API/test/ImmutableCompositeFunctionTest.h b/Framework/API/test/ImmutableCompositeFunctionTest.h
index 336aaa437dc..816c95cfa8d 100644
--- a/Framework/API/test/ImmutableCompositeFunctionTest.h
+++ b/Framework/API/test/ImmutableCompositeFunctionTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMMUTABLECOMPOSITEFUNCTIONTEST_H_
-#define IMMUTABLECOMPOSITEFUNCTIONTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -334,4 +333,3 @@ public:
   }
 };
 
-#endif /*IMMUTABLECOMPOSITEFUNCTIONTEST_H_*/
diff --git a/Framework/API/test/ImplicitFunctionFactoryTest.h b/Framework/API/test/ImplicitFunctionFactoryTest.h
index f94b5c4a70e..56c31df4e6c 100644
--- a/Framework/API/test/ImplicitFunctionFactoryTest.h
+++ b/Framework/API/test/ImplicitFunctionFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMPLICIT_FUNCTION_FACTORY_TEST_H_
-#define IMPLICIT_FUNCTION_FACTORY_TEST_H_
+#pragma once
 
 #include "MantidAPI/ImplicitFunctionFactory.h"
 #include "MantidAPI/ImplicitFunctionParameter.h"
@@ -193,4 +192,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/ImplicitFunctionParameterParserFactoryTest.h b/Framework/API/test/ImplicitFunctionParameterParserFactoryTest.h
index ba81f84ee36..66eb4d86a13 100644
--- a/Framework/API/test/ImplicitFunctionParameterParserFactoryTest.h
+++ b/Framework/API/test/ImplicitFunctionParameterParserFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMPLICIT_FUNCTION_PARAMETER_PARSER_FACTORY_TEST_H_
-#define IMPLICIT_FUNCTION_PARAMETER_PARSER_FACTORY_TEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 #include <vector>
@@ -102,4 +101,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/ImplicitFunctionParserFactoryTest.h b/Framework/API/test/ImplicitFunctionParserFactoryTest.h
index e1db7e32ba7..46ff50223d0 100644
--- a/Framework/API/test/ImplicitFunctionParserFactoryTest.h
+++ b/Framework/API/test/ImplicitFunctionParserFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef IMPLICIT_FUNCTION_PARSER_FACTORY_TEST_H_
-#define IMPLICIT_FUNCTION_PARSER_FACTORY_TEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 #include <vector>
@@ -104,4 +103,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/IncreasingAxisValidatorTest.h b/Framework/API/test/IncreasingAxisValidatorTest.h
index 7bfa8b26ec0..9209aaebc98 100644
--- a/Framework/API/test/IncreasingAxisValidatorTest.h
+++ b/Framework/API/test/IncreasingAxisValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_INCREASINGAXISVALIDATORTEST_H_
-#define MANTID_API_INCREASINGAXISVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -62,4 +61,3 @@ private:
   Mantid::API::IncreasingAxisValidator validator;
 };
 
-#endif /* MANTID_API_INCREASINGAXISVALIDATORTEST_H_ */
diff --git a/Framework/API/test/IndexPropertyTest.h b/Framework/API/test/IndexPropertyTest.h
index acffe60e051..72b6893de25 100644
--- a/Framework/API/test/IndexPropertyTest.h
+++ b/Framework/API/test/IndexPropertyTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_INDEXPROPERTYTEST_H_
-#define MANTID_API_INDEXPROPERTYTEST_H_
+#pragma once
 
 #include "MantidAPI/IndexProperty.h"
 #include "MantidAPI/IndexTypeProperty.h"
@@ -198,4 +197,3 @@ private:
   IndexTypeProperty m_itypeProp;
 };
 
-#endif /* MANTID_API_INDEXPROPERTYTEST_H_ */
diff --git a/Framework/API/test/IndexTypePropertyTest.h b/Framework/API/test/IndexTypePropertyTest.h
index 1b3d2e9bab2..132ec4cf316 100644
--- a/Framework/API/test/IndexTypePropertyTest.h
+++ b/Framework/API/test/IndexTypePropertyTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_INDEXTYPEPROPERTYTEST_H_
-#define MANTID_API_INDEXTYPEPROPERTYTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -94,4 +93,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_INDEXTYPEPROPERTYTEST_H_ */
\ No newline at end of file
diff --git a/Framework/API/test/InstrumentDataServiceTest.h b/Framework/API/test/InstrumentDataServiceTest.h
index 5c9a41fb78e..ff3ec15bc96 100644
--- a/Framework/API/test/InstrumentDataServiceTest.h
+++ b/Framework/API/test/InstrumentDataServiceTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef INSTRUMENTDATASERVICETEST_H_
-#define INSTRUMENTDATASERVICETEST_H_
+#pragma once
 
 #include "MantidAPI/FrameworkManager.h"
 #include "MantidAPI/InstrumentDataService.h"
@@ -121,4 +120,3 @@ private:
   boost::shared_ptr<Instrument> inst1, inst2;
 };
 
-#endif /*INSTRUMENTDATASERVICETEST_H_*/
diff --git a/Framework/API/test/InstrumentValidatorTest.h b/Framework/API/test/InstrumentValidatorTest.h
index 907dc07f793..0da87309394 100644
--- a/Framework/API/test/InstrumentValidatorTest.h
+++ b/Framework/API/test/InstrumentValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_INSTRUMENTVALIDATORTEST_H_
-#define MANTID_API_INSTRUMENTVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -53,4 +52,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_INSTRUMENTVALIDATORTEST_H_ */
diff --git a/Framework/API/test/LatticeDomainTest.h b/Framework/API/test/LatticeDomainTest.h
index b1ed9e0d0d4..2971dd36fbb 100644
--- a/Framework/API/test/LatticeDomainTest.h
+++ b/Framework/API/test/LatticeDomainTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_LATTICEDOMAINTEST_H_
-#define MANTID_API_LATTICEDOMAINTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -55,4 +54,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_LATTICEDOMAINTEST_H_ */
diff --git a/Framework/API/test/LiveListenerFactoryTest.h b/Framework/API/test/LiveListenerFactoryTest.h
index 0a8a49e8164..2ecf380b507 100644
--- a/Framework/API/test/LiveListenerFactoryTest.h
+++ b/Framework/API/test/LiveListenerFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef LIVELISTENERFACTORYTEST_H_
-#define LIVELISTENERFACTORYTEST_H_
+#pragma once
 
 #include "LiveListenerTest.h"
 #include "MantidAPI/Algorithm.h"
@@ -170,4 +169,3 @@ public:
   }
 };
 
-#endif /* LIVELISTENERFACTORYTEST_H_ */
diff --git a/Framework/API/test/LiveListenerTest.h b/Framework/API/test/LiveListenerTest.h
index 2f70561e7cd..b47442255d5 100644
--- a/Framework/API/test/LiveListenerTest.h
+++ b/Framework/API/test/LiveListenerTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef LIVELISTENER_TEST_H_
-#define LIVELISTENER_TEST_H_
+#pragma once
 
 #include "MantidAPI/IAlgorithm.h"
 #include "MantidAPI/LiveListener.h"
@@ -48,4 +47,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/LogFilterGeneratorTest.h b/Framework/API/test/LogFilterGeneratorTest.h
index 0cd05a56480..b7ef6546ab9 100644
--- a/Framework/API/test/LogFilterGeneratorTest.h
+++ b/Framework/API/test/LogFilterGeneratorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_LOGFILTERGENERATORTEST_H_
-#define MANTID_API_LOGFILTERGENERATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -190,4 +189,3 @@ private:
   }
 };
 
-#endif /* MANTID_API_LOGFILTERGENERATORTEST_H_ */
diff --git a/Framework/API/test/LogManagerTest.h b/Framework/API/test/LogManagerTest.h
index a6e5733416f..caf94e927e7 100644
--- a/Framework/API/test/LogManagerTest.h
+++ b/Framework/API/test/LogManagerTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef LOG_MANAGER_TEST_H_
-#define LOG_MANAGER_TEST_H_
+#pragma once
 
 #include "MantidAPI/LogManager.h"
 #include "MantidGeometry/Instrument/Goniometer.h"
@@ -592,4 +591,3 @@ public:
   std::string m_propName;
 };
 
-#endif
diff --git a/Framework/API/test/MDFrameValidatorTest.h b/Framework/API/test/MDFrameValidatorTest.h
index b1a508b6840..b3eec99eafc 100644
--- a/Framework/API/test/MDFrameValidatorTest.h
+++ b/Framework/API/test/MDFrameValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_MDUNITVALIDATOR_TEST_H
-#define MANTID_MDUNITVALIDATOR_TEST_H
+#pragma once
 
 #include <boost/make_shared.hpp>
 #include <cxxtest/TestSuite.h>
@@ -79,4 +78,3 @@ public:
   };
 };
 
-#endif // MANTID_MDUNITVALIDATOR_TEST_H
diff --git a/Framework/API/test/MDGeometryTest.h b/Framework/API/test/MDGeometryTest.h
index c8cc963c9b3..783867834aa 100644
--- a/Framework/API/test/MDGeometryTest.h
+++ b/Framework/API/test/MDGeometryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MDGEOMETRYTEST_H_
-#define MANTID_API_MDGEOMETRYTEST_H_
+#pragma once
 
 #include "MantidAPI/AnalysisDataService.h"
 #include "MantidAPI/IMDWorkspace.h"
@@ -308,4 +307,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_MDGEOMETRYTEST_H_ */
diff --git a/Framework/API/test/MatrixWorkspaceMDIteratorTest.h b/Framework/API/test/MatrixWorkspaceMDIteratorTest.h
index 8e06b97a699..efbcfb2f8fe 100644
--- a/Framework/API/test/MatrixWorkspaceMDIteratorTest.h
+++ b/Framework/API/test/MatrixWorkspaceMDIteratorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MATRIXWORKSPACEMDITERATORTEST_H_
-#define MANTID_API_MATRIXWORKSPACEMDITERATORTEST_H_
+#pragma once
 
 #include "MantidAPI/MatrixWorkspaceMDIterator.h"
 #include "MantidAPI/SpectrumInfo.h"
@@ -179,4 +178,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_MATRIXWORKSPACEMDITERATORTEST_H_ */
diff --git a/Framework/API/test/MatrixWorkspaceTest.h b/Framework/API/test/MatrixWorkspaceTest.h
index 26918b99e08..528f69c853d 100644
--- a/Framework/API/test/MatrixWorkspaceTest.h
+++ b/Framework/API/test/MatrixWorkspaceTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef WORKSPACETEST_H_
-#define WORKSPACETEST_H_
+#pragma once
 
 #include "MantidAPI/AnalysisDataService.h"
 #include "MantidAPI/ISpectrum.h"
@@ -2403,4 +2402,3 @@ private:
   boost::shared_ptr<Mantid::Geometry::ParameterMap> m_paramMap;
 };
 
-#endif /*WORKSPACETEST_H_*/
diff --git a/Framework/API/test/MuParserUtilsTest.h b/Framework/API/test/MuParserUtilsTest.h
index 9d25222cb27..2ec4d6ce9f7 100644
--- a/Framework/API/test/MuParserUtilsTest.h
+++ b/Framework/API/test/MuParserUtilsTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MUPARSERUTILSTEST_H_
-#define MANTID_API_MUPARSERUTILSTEST_H_
+#pragma once
 
 #include "MantidAPI/MuParserUtils.h"
 #include <cxxtest/TestSuite.h>
@@ -75,4 +74,3 @@ private:
   }
 };
 
-#endif /* MANTID_API_MUPARSERUTILSTEST_H_ */
diff --git a/Framework/API/test/MultiDomainFunctionTest.h b/Framework/API/test/MultiDomainFunctionTest.h
index 239b97ddac6..de87f5bd59e 100644
--- a/Framework/API/test/MultiDomainFunctionTest.h
+++ b/Framework/API/test/MultiDomainFunctionTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MULTIDOMAINFUNCTIONTEST_H_
-#define MULTIDOMAINFUNCTIONTEST_H_
+#pragma once
 
 #include "MantidAPI/FunctionDomain1D.h"
 #include "MantidAPI/FunctionFactory.h"
@@ -505,4 +504,3 @@ private:
   JointDomain domain;
 };
 
-#endif /*MULTIDOMAINFUNCTIONTEST_H_*/
diff --git a/Framework/API/test/MultiPeriodGroupAlgorithmTest.h b/Framework/API/test/MultiPeriodGroupAlgorithmTest.h
index 9797626f1df..3ce5db2744e 100644
--- a/Framework/API/test/MultiPeriodGroupAlgorithmTest.h
+++ b/Framework/API/test/MultiPeriodGroupAlgorithmTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MultiPeriodGroupAlgorithmTEST_H_
-#define MANTID_API_MultiPeriodGroupAlgorithmTEST_H_
+#pragma once
 
 #include "MantidAPI/MultiPeriodGroupAlgorithm.h"
 #include "MantidKernel/ArrayProperty.h"
@@ -252,4 +251,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_MultiPeriodGroupAlgorithmTEST_H_ */
diff --git a/Framework/API/test/MultiPeriodGroupTestBase.h b/Framework/API/test/MultiPeriodGroupTestBase.h
index 7a2f320cc13..853dc6d6222 100644
--- a/Framework/API/test/MultiPeriodGroupTestBase.h
+++ b/Framework/API/test/MultiPeriodGroupTestBase.h
@@ -11,8 +11,7 @@
  *      Author: spu92482
  */
 
-#ifndef MANTID_API_MULTIPERIODGROUPTESTBASE_H_
-#define MANTID_API_MULTIPERIODGROUPTESTBASE_H_
+#pragma once
 
 #include "MantidAPI/AnalysisDataService.h"
 #include "MantidAPI/MatrixWorkspace.h"
@@ -63,4 +62,3 @@ protected:
   }
 };
 
-#endif /* MANTID_API_MULTIPERIODGROUPTESTBASE_H_ */
diff --git a/Framework/API/test/MultiPeriodGroupWorkerTest.h b/Framework/API/test/MultiPeriodGroupWorkerTest.h
index 4cd57d0cbc5..2e1db743612 100644
--- a/Framework/API/test/MultiPeriodGroupWorkerTest.h
+++ b/Framework/API/test/MultiPeriodGroupWorkerTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MULTIPERIODGROUPWORKERTEST_H_
-#define MANTID_API_MULTIPERIODGROUPWORKERTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -99,4 +98,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_MULTIPERIODGROUPWORKERTEST_H_ */
diff --git a/Framework/API/test/MultipleExperimentInfosTest.h b/Framework/API/test/MultipleExperimentInfosTest.h
index dd2f295385d..f13016ed3ab 100644
--- a/Framework/API/test/MultipleExperimentInfosTest.h
+++ b/Framework/API/test/MultipleExperimentInfosTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MULTIPLEEXPERIMENTINFOSTEST_H_
-#define MANTID_API_MULTIPLEEXPERIMENTINFOSTEST_H_
+#pragma once
 
 #include "MantidKernel/System.h"
 #include "MantidKernel/Timer.h"
@@ -74,4 +73,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_MULTIPLEEXPERIMENTINFOSTEST_H_ */
diff --git a/Framework/API/test/MultipleFilePropertyTest.h b/Framework/API/test/MultipleFilePropertyTest.h
index 24da8f9d48c..ae45fa385e5 100644
--- a/Framework/API/test/MultipleFilePropertyTest.h
+++ b/Framework/API/test/MultipleFilePropertyTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_MULTIPLEFILEPROPERTYTEST_H_
-#define MANTID_API_MULTIPLEFILEPROPERTYTEST_H_
+#pragma once
 
 #include "MantidAPI/FileProperty.h"
 #include "MantidAPI/MultipleFileProperty.h"
@@ -765,4 +764,3 @@ private:
   }
 };
 
-#endif /* MANTID_API_MULTIPLEFILEPROPERTYTEST_H_ */
diff --git a/Framework/API/test/NotebookBuilderTest.h b/Framework/API/test/NotebookBuilderTest.h
index eadac1881d6..940fc9e4016 100644
--- a/Framework/API/test/NotebookBuilderTest.h
+++ b/Framework/API/test/NotebookBuilderTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_NOTEBOOKBUILDERTEST_H_
-#define MANTID_NOTEBOOKBUILDERTEST_H_
+#pragma once
 
 #include <algorithm>
 #include <cxxtest/TestSuite.h>
@@ -352,4 +351,3 @@ public:
   }
 };
 
-#endif // MANTID_NOTEBOOKBUILDERTEST_H_
diff --git a/Framework/API/test/NotebookWriterTest.h b/Framework/API/test/NotebookWriterTest.h
index 745f68f0ae5..186301de78d 100644
--- a/Framework/API/test/NotebookWriterTest.h
+++ b/Framework/API/test/NotebookWriterTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_NOTEBOOKWRITERTEST_H_
-#define MANTID_NOTEBOOKWRITERTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -61,4 +60,3 @@ public:
   }
 };
 
-#endif // MANTID_NOTEBOOKWRITERTEST_H_
diff --git a/Framework/API/test/NumericAxisTest.h b/Framework/API/test/NumericAxisTest.h
index 2fc2a4c9268..6b7a47ea0d2 100644
--- a/Framework/API/test/NumericAxisTest.h
+++ b/Framework/API/test/NumericAxisTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef NUMERICAXISTEST_H_
-#define NUMERICAXISTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -225,4 +224,3 @@ private:
   Axis *numericAxis;
 };
 
-#endif /*NUMERICAXISTEST_H_*/
diff --git a/Framework/API/test/NumericAxisValidatorTest.h b/Framework/API/test/NumericAxisValidatorTest.h
index 2c32bce2f91..ef51c7186d9 100644
--- a/Framework/API/test/NumericAxisValidatorTest.h
+++ b/Framework/API/test/NumericAxisValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_NUMERICAXISVALIDATORTEST_H_
-#define MANTID_API_NUMERICAXISVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -51,4 +50,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_NUMERICAXISVALIDATORTEST_H_ */
diff --git a/Framework/API/test/OrientedLatticeValidatorTest.h b/Framework/API/test/OrientedLatticeValidatorTest.h
index 51ee7075625..6ef9c3a3575 100644
--- a/Framework/API/test/OrientedLatticeValidatorTest.h
+++ b/Framework/API/test/OrientedLatticeValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_ORIENTEDLATTICEVALIDATOR_TEST_H
-#define MANTID_ORIENTEDLATTICEVALIDATOR_TEST_H
+#pragma once
 
 #include <boost/make_shared.hpp>
 #include <cxxtest/TestSuite.h>
@@ -50,4 +49,3 @@ public:
   };
 };
 
-#endif // MANTID_ORIENTEDLATTICEVALIDATOR_TEST_H
diff --git a/Framework/API/test/ParamFunctionAttributeHolderTest.h b/Framework/API/test/ParamFunctionAttributeHolderTest.h
index db87f0da160..71e026e2618 100644
--- a/Framework/API/test/ParamFunctionAttributeHolderTest.h
+++ b/Framework/API/test/ParamFunctionAttributeHolderTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef PARAMFUNCTIONATTRIBUTEHOLDERTEST_H_
-#define PARAMFUNCTIONATTRIBUTEHOLDERTEST_H_
+#pragma once
 
 #include "MantidAPI/ParamFunction.h"
 #include <cxxtest/TestSuite.h>
@@ -90,4 +89,3 @@ public:
   }
 };
 
-#endif /* PARAMFUNCTIONATTRIBUTEHOLDERTEST_H_ */
diff --git a/Framework/API/test/ParameterReferenceTest.h b/Framework/API/test/ParameterReferenceTest.h
index e05e249ab4d..2bf2307447e 100644
--- a/Framework/API/test/ParameterReferenceTest.h
+++ b/Framework/API/test/ParameterReferenceTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef PARAMETERREFERENCETEST_H_
-#define PARAMETERREFERENCETEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -128,4 +127,3 @@ public:
   }
 };
 
-#endif /*PARAMETERREFERENCETEST_H_*/
diff --git a/Framework/API/test/ParameterTieTest.h b/Framework/API/test/ParameterTieTest.h
index 6ddfe2e1399..c655bddd583 100644
--- a/Framework/API/test/ParameterTieTest.h
+++ b/Framework/API/test/ParameterTieTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef PARAMETERTIETEST_H_
-#define PARAMETERTIETEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -371,4 +370,3 @@ private:
   }
 };
 
-#endif /*PARAMETERTIETEST_H_*/
diff --git a/Framework/API/test/PeakFunctionIntegratorTest.h b/Framework/API/test/PeakFunctionIntegratorTest.h
index c7e9e83c3d1..e007ca6dfe0 100644
--- a/Framework/API/test/PeakFunctionIntegratorTest.h
+++ b/Framework/API/test/PeakFunctionIntegratorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef PEAKFUNCTIONINTEGRATORTEST_H
-#define PEAKFUNCTIONINTEGRATORTEST_H
+#pragma once
 
 #include "MantidAPI/PeakFunctionIntegrator.h"
 #include <cxxtest/TestSuite.h>
@@ -195,4 +194,3 @@ public:
   }
 };
 
-#endif // PEAKFUNCTIONINTEGRATORTEST_H
diff --git a/Framework/API/test/PrecompiledHeader.h b/Framework/API/test/PrecompiledHeader.h
index f9370b7db20..2b4559aad07 100644
--- a/Framework/API/test/PrecompiledHeader.h
+++ b/Framework/API/test/PrecompiledHeader.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_APITEST_PRECOMPILED_HEADER_H_
-#define MANTID_APITEST_PRECOMPILED_HEADER_H_
+#pragma once
 
 // cxxtest
 #include <cxxtest/WrappedTestSuite.h>
@@ -15,4 +14,3 @@
 #include <string>
 #include <vector>
 
-#endif // MANTID_API_PRECOMPILED_HEADER_H_
\ No newline at end of file
diff --git a/Framework/API/test/ProgressTest.h b/Framework/API/test/ProgressTest.h
index 155ce82ceb9..48997574932 100644
--- a/Framework/API/test/ProgressTest.h
+++ b/Framework/API/test/ProgressTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef PROGRESSTEST_H_
-#define PROGRESSTEST_H_
+#pragma once
 
 #include "MantidAPI/Progress.h"
 #include <cxxtest/TestSuite.h>
@@ -27,4 +26,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/ProjectionTest.h b/Framework/API/test/ProjectionTest.h
index eb51d660366..68226c924f6 100644
--- a/Framework/API/test/ProjectionTest.h
+++ b/Framework/API/test/ProjectionTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_PROJECTIONTEST_H_
-#define MANTID_API_PROJECTIONTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -290,4 +289,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_PROJECTIONTEST_H_ */
diff --git a/Framework/API/test/PropertyManagerHelper.h b/Framework/API/test/PropertyManagerHelper.h
index a717d8208b3..d60ddf0e1e5 100644
--- a/Framework/API/test/PropertyManagerHelper.h
+++ b/Framework/API/test/PropertyManagerHelper.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef APITEST_PROPERTYMANAGERHELPER_H_
-#define APITEST_PROPERTYMANAGERHELPER_H_
+#pragma once
 
 #include "MantidKernel/PropertyManager.h"
 
@@ -22,4 +21,3 @@ public:
   using PropertyManager::setProperty;
 };
 
-#endif
diff --git a/Framework/API/test/RawCountValidatorTest.h b/Framework/API/test/RawCountValidatorTest.h
index 9b3c08e1d7c..bc538c1e498 100644
--- a/Framework/API/test/RawCountValidatorTest.h
+++ b/Framework/API/test/RawCountValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_RAWCOUNTVALIDATORTEST_H_
-#define MANTID_API_RAWCOUNTVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -41,4 +40,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_RAWCOUNTVALIDATORTEST_H_ */
\ No newline at end of file
diff --git a/Framework/API/test/RemoteJobManagerFactoryTest.h b/Framework/API/test/RemoteJobManagerFactoryTest.h
index a8a339d050b..34140a9e85e 100644
--- a/Framework/API/test/RemoteJobManagerFactoryTest.h
+++ b/Framework/API/test/RemoteJobManagerFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef REMOTEJOBMANAGERFACTORYTEST_H_
-#define REMOTEJOBMANAGERFACTORYTEST_H_
+#pragma once
 
 #include "MantidAPI/RemoteJobManagerFactory.h"
 #include "MantidKernel/ConfigService.h"
@@ -226,4 +225,3 @@ const std::string RemoteJobManagerFactoryTest::SNSFac = "SNS";
 const std::string RemoteJobManagerFactoryTest::ISISFac = "ISIS";
 const std::string RemoteJobManagerFactoryTest::FermiName = "Fermi";
 
-#endif /* REMOTEJOBMANAGERFACTORYTEST_H_ */
diff --git a/Framework/API/test/ResizeRectangularDetectorHelperTest.h b/Framework/API/test/ResizeRectangularDetectorHelperTest.h
index a0dcba5b793..6aba92a783b 100644
--- a/Framework/API/test/ResizeRectangularDetectorHelperTest.h
+++ b/Framework/API/test/ResizeRectangularDetectorHelperTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_RESIZERECTANGULARDETECTORHELPERTEST_H_
-#define MANTID_API_RESIZERECTANGULARDETECTORHELPERTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -79,4 +78,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_RESIZERECTANGULARDETECTORHELPERTEST_H_ */
diff --git a/Framework/API/test/RunTest.h b/Framework/API/test/RunTest.h
index 8522c39a36d..e6d9544f5d6 100644
--- a/Framework/API/test/RunTest.h
+++ b/Framework/API/test/RunTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef RUNTEST_H_
-#define RUNTEST_H_
+#pragma once
 
 #include "MantidAPI/Run.h"
 #include "MantidGeometry/Instrument/Goniometer.h"
@@ -643,4 +642,3 @@ public:
   std::string m_propName;
 };
 
-#endif
diff --git a/Framework/API/test/SampleShapeValidatorTest.h b/Framework/API/test/SampleShapeValidatorTest.h
index eda018dbddb..830b0662815 100644
--- a/Framework/API/test/SampleShapeValidatorTest.h
+++ b/Framework/API/test/SampleShapeValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SAMPLESHAPEVALIDATORTEST_H_
-#define MANTID_API_SAMPLESHAPEVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -47,4 +46,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_SAMPLESHAPEVALIDATORTEST_H_ */
diff --git a/Framework/API/test/SampleTest.h b/Framework/API/test/SampleTest.h
index 1885279be63..4dcc4cc5b40 100644
--- a/Framework/API/test/SampleTest.h
+++ b/Framework/API/test/SampleTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef TESTSAMPLE_H_
-#define TESTSAMPLE_H_
+#pragma once
 
 #include "MantidAPI/Sample.h"
 #include "MantidGeometry/Crystal/CrystalStructure.h"
@@ -362,4 +361,3 @@ public:
   }
 };
 
-#endif /*TESTSAMPLE_H_*/
diff --git a/Framework/API/test/SampleValidatorTest.h b/Framework/API/test/SampleValidatorTest.h
index 63b273fb0f1..677e8db4024 100644
--- a/Framework/API/test/SampleValidatorTest.h
+++ b/Framework/API/test/SampleValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SAMPLEVALIDATORTEST_H_
-#define MANTID_API_SAMPLEVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -49,4 +48,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_SAMPLEVALIDATORTEST_H_ */
diff --git a/Framework/API/test/ScopedWorkspaceTest.h b/Framework/API/test/ScopedWorkspaceTest.h
index bfd0fe32223..d973929dde9 100644
--- a/Framework/API/test/ScopedWorkspaceTest.h
+++ b/Framework/API/test/ScopedWorkspaceTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SCOPEDWORKSPACETEST_H_
-#define MANTID_API_SCOPEDWORKSPACETEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -220,4 +219,3 @@ private:
   AnalysisDataServiceImpl &m_ads;
 };
 
-#endif /* MANTID_API_SCOPEDWORKSPACETEST_H_ */
diff --git a/Framework/API/test/ScriptBuilderTest.h b/Framework/API/test/ScriptBuilderTest.h
index 5791a6e12da..860052e79b6 100644
--- a/Framework/API/test/ScriptBuilderTest.h
+++ b/Framework/API/test/ScriptBuilderTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_SCRIPTBUILDERTEST_H_
-#define MANTID_SCRIPTBUILDERTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -591,4 +590,3 @@ private:
   MatrixWorkspace_sptr m_testWS;
 };
 
-#endif // MANTID_SCRIPTBUILDERTEST_H_
diff --git a/Framework/API/test/SingleCountValidatorTest.h b/Framework/API/test/SingleCountValidatorTest.h
index 833a21f2be7..c8d807a9438 100644
--- a/Framework/API/test/SingleCountValidatorTest.h
+++ b/Framework/API/test/SingleCountValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SINGLECOUNTVALIDATORTEST_H_
-#define MANTID_API_SINGLECOUNTVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -86,4 +85,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_SINGLECOUNTVALIDATORTEST_H_ */
diff --git a/Framework/API/test/SpectraAxisTest.h b/Framework/API/test/SpectraAxisTest.h
index e8fe835ad36..4cfeb92a497 100644
--- a/Framework/API/test/SpectraAxisTest.h
+++ b/Framework/API/test/SpectraAxisTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef SPECTRAAXISTEST_H_
-#define SPECTRAAXISTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -127,4 +126,3 @@ private:
   Axis *spectraAxis;
 };
 
-#endif /*SPECTRAAXISTEST_H_*/
diff --git a/Framework/API/test/SpectraAxisValidatorTest.h b/Framework/API/test/SpectraAxisValidatorTest.h
index 9b23c9bd718..c91efa34dd5 100644
--- a/Framework/API/test/SpectraAxisValidatorTest.h
+++ b/Framework/API/test/SpectraAxisValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRAAXISVALIDATORTEST_H_
-#define MANTID_API_SPECTRAAXISVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -51,4 +50,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_SPECTRAAXISVALIDATORTEST_H_ */
diff --git a/Framework/API/test/SpectrumDetectorMappingTest.h b/Framework/API/test/SpectrumDetectorMappingTest.h
index 18a918d1605..bcf712d2197 100644
--- a/Framework/API/test/SpectrumDetectorMappingTest.h
+++ b/Framework/API/test/SpectrumDetectorMappingTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRUMDETECTORMAPPINGTEST_H_
-#define MANTID_API_SPECTRUMDETECTORMAPPINGTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -165,4 +164,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_SPECTRUMDETECTORMAPPINGTEST_H_ */
diff --git a/Framework/API/test/SpectrumInfoTest.h b/Framework/API/test/SpectrumInfoTest.h
index 28dc7e43a87..0348dd4470b 100644
--- a/Framework/API/test/SpectrumInfoTest.h
+++ b/Framework/API/test/SpectrumInfoTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_SPECTRUMINFOTEST_H_
-#define MANTID_API_SPECTRUMINFOTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -659,4 +658,3 @@ private:
   WorkspaceTester m_workspace;
 };
 
-#endif /* MANTID_API_SPECTRUMINFOTEST_H_ */
diff --git a/Framework/API/test/TempFunctionTest.h b/Framework/API/test/TempFunctionTest.h
index 8432d1c096c..e40e088c275 100644
--- a/Framework/API/test/TempFunctionTest.h
+++ b/Framework/API/test/TempFunctionTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef TEMPFUNCTIONTEST_H_
-#define TEMPFUNCTIONTEST_H_
+#pragma once
 
 #include "MantidAPI/IFunctionMW.h"
 #include "MantidAPI/ParamFunction.h"
@@ -83,4 +82,3 @@ public:
   }
 };
 
-#endif /*TEMPFUNCTIONTEST_H_*/
diff --git a/Framework/API/test/TextAxisTest.h b/Framework/API/test/TextAxisTest.h
index b32810b03dd..776a06a368b 100644
--- a/Framework/API/test/TextAxisTest.h
+++ b/Framework/API/test/TextAxisTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef TEXTAXISTEST_H_
-#define TEXTAXISTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -137,4 +136,3 @@ public:
   }
 };
 
-#endif /*TEXTAXISTEST_H_*/
diff --git a/Framework/API/test/TransformScaleFactoryTest.h b/Framework/API/test/TransformScaleFactoryTest.h
index af27ddaf8c4..c65d736625c 100644
--- a/Framework/API/test/TransformScaleFactoryTest.h
+++ b/Framework/API/test/TransformScaleFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef TRANSFORMSCALEFACTORYTEST_H_
-#define TRANSFORMSCALEFACTORYTEST_H_
+#pragma once
 
 #include "ITransformScale.h"
 #include "MantidAPI/TransformScaleFactory.h"
@@ -39,4 +38,3 @@ private:
   TransformScaleFactoryImpl &factory;
 };
 
-#endif /* TRANSFORMSCALEFACTORYTEST_H_ */
diff --git a/Framework/API/test/VectorParameterParserTest.h b/Framework/API/test/VectorParameterParserTest.h
index 80a94317a09..df07f208dd2 100644
--- a/Framework/API/test/VectorParameterParserTest.h
+++ b/Framework/API/test/VectorParameterParserTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef VECTOR_IMPLICIT_FUNCTION_PARAMETER_PARSER_TEST_H_
-#define VECTOR_IMPLICIT_FUNCTION_PARAMETER_PARSER_TEST_H_
+#pragma once
 
 #include "MantidAPI/VectorParameter.h"
 #include "MantidAPI/VectorParameterParser.h"
@@ -179,4 +178,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/VectorParameterTest.h b/Framework/API/test/VectorParameterTest.h
index b237a50e207..0dc750e43e1 100644
--- a/Framework/API/test/VectorParameterTest.h
+++ b/Framework/API/test/VectorParameterTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef VECTOR_IMPLICIT_FUNCTION_PARAMETER_TEST_H_
-#define VECTOR_IMPLICIT_FUNCTION_PARAMETER_TEST_H_
+#pragma once
 
 #include "MantidAPI/VectorParameter.h"
 #include <cxxtest/TestSuite.h>
@@ -135,4 +134,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/WorkspaceFactoryTest.h b/Framework/API/test/WorkspaceFactoryTest.h
index e6401e2bd6f..2997e0c6618 100644
--- a/Framework/API/test/WorkspaceFactoryTest.h
+++ b/Framework/API/test/WorkspaceFactoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef WORKSPACEFACTORYTEST_H_
-#define WORKSPACEFACTORYTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 #include <vector>
@@ -152,4 +151,3 @@ public:
   }
 };
 
-#endif /*WORKSPACEFACTORYTEST_H_*/
diff --git a/Framework/API/test/WorkspaceGroupTest.h b/Framework/API/test/WorkspaceGroupTest.h
index e0810b9763a..fa764883f98 100644
--- a/Framework/API/test/WorkspaceGroupTest.h
+++ b/Framework/API/test/WorkspaceGroupTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACEGROUPTEST_H_
-#define MANTID_API_WORKSPACEGROUPTEST_H_
+#pragma once
 
 #include "MantidAPI/AnalysisDataService.h"
 #include "MantidAPI/Run.h"
@@ -485,4 +484,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_WORKSPACEGROUPTEST_H_ */
diff --git a/Framework/API/test/WorkspaceHasDxValidatorTest.h b/Framework/API/test/WorkspaceHasDxValidatorTest.h
index 7713fa5e0f2..b4f45b726ef 100644
--- a/Framework/API/test/WorkspaceHasDxValidatorTest.h
+++ b/Framework/API/test/WorkspaceHasDxValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACEHASDXVALIDATORTEST_H_
-#define MANTID_API_WORKSPACEHASDXVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -42,4 +41,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_WORKSPACEHASDXVALIDATORTEST_H_ */
diff --git a/Framework/API/test/WorkspaceHistoryIOTest.h b/Framework/API/test/WorkspaceHistoryIOTest.h
index e82dfe93d0d..fa0c415b7b1 100644
--- a/Framework/API/test/WorkspaceHistoryIOTest.h
+++ b/Framework/API/test/WorkspaceHistoryIOTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef WORKSPACEHISTORYIOTEST_H_
-#define WORKSPACEHISTORYIOTEST_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/AlgorithmFactory.h"
@@ -474,4 +473,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/WorkspaceHistoryTest.h b/Framework/API/test/WorkspaceHistoryTest.h
index 1b7c732c753..9da45b5da18 100644
--- a/Framework/API/test/WorkspaceHistoryTest.h
+++ b/Framework/API/test/WorkspaceHistoryTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef WORKSPACEHISTORYTEST_H_
-#define WORKSPACEHISTORYTEST_H_
+#pragma once
 
 #include "MantidAPI/Algorithm.h"
 #include "MantidAPI/AlgorithmFactory.h"
@@ -229,4 +228,3 @@ private:
   WorkspaceHistory m_1000000Histories2;
 };
 
-#endif
diff --git a/Framework/API/test/WorkspaceNearestNeighbourInfoTest.h b/Framework/API/test/WorkspaceNearestNeighbourInfoTest.h
index 3f7428717d0..0ff15d21a21 100644
--- a/Framework/API/test/WorkspaceNearestNeighbourInfoTest.h
+++ b/Framework/API/test/WorkspaceNearestNeighbourInfoTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_NEARESTNEIGHBOURINFOTEST_H_
-#define MANTID_API_NEARESTNEIGHBOURINFOTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -66,4 +65,3 @@ private:
   WorkspaceTester workspace;
 };
 
-#endif /* MANTID_API_NEARESTNEIGHBOURINFOTEST_H_ */
diff --git a/Framework/API/test/WorkspaceNearestNeighboursTest.h b/Framework/API/test/WorkspaceNearestNeighboursTest.h
index c8447ad66ef..c60002b2bdf 100644
--- a/Framework/API/test/WorkspaceNearestNeighboursTest.h
+++ b/Framework/API/test/WorkspaceNearestNeighboursTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_TEST_GEOMETRY_NEARESTNEIGHBOURS
-#define MANTID_TEST_GEOMETRY_NEARESTNEIGHBOURS
+#pragma once
 
 #include "MantidAPI/SpectrumInfo.h"
 #include "MantidAPI/WorkspaceNearestNeighbours.h"
@@ -241,4 +240,3 @@ public:
   }
 };
 
-#endif /* MANTID_TEST_GEOMETRY_NEARESTNEIGHBOURS */
diff --git a/Framework/API/test/WorkspaceOpOverloadsTest.h b/Framework/API/test/WorkspaceOpOverloadsTest.h
index da551009eb8..3e46f32b5bc 100644
--- a/Framework/API/test/WorkspaceOpOverloadsTest.h
+++ b/Framework/API/test/WorkspaceOpOverloadsTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef WORKSPACEOPOVERLOADSTEST_H_
-#define WORKSPACEOPOVERLOADSTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -174,4 +173,3 @@ public:
   }
 };
 
-#endif
diff --git a/Framework/API/test/WorkspacePropertyTest.h b/Framework/API/test/WorkspacePropertyTest.h
index 5e53ae3b7c9..8b443280abd 100644
--- a/Framework/API/test/WorkspacePropertyTest.h
+++ b/Framework/API/test/WorkspacePropertyTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef WORKSPACEPROPERTYTEST_H_
-#define WORKSPACEPROPERTYTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -417,4 +416,3 @@ private:
   WorkspacePropertyWorkspace_uptr wsp6;
 };
 
-#endif /*WORKSPACEPROPERTYTEST_H_*/
diff --git a/Framework/API/test/WorkspaceUnitValidatorTest.h b/Framework/API/test/WorkspaceUnitValidatorTest.h
index 3c36bd81f63..9ec72036c73 100644
--- a/Framework/API/test/WorkspaceUnitValidatorTest.h
+++ b/Framework/API/test/WorkspaceUnitValidatorTest.h
@@ -4,8 +4,7 @@
 //     NScD Oak Ridge National Laboratory, European Spallation Source
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
-#ifndef MANTID_API_WORKSPACEUNITVALIDATORTEST_H_
-#define MANTID_API_WORKSPACEUNITVALIDATORTEST_H_
+#pragma once
 
 #include <cxxtest/TestSuite.h>
 
@@ -39,4 +38,3 @@ public:
   }
 };
 
-#endif /* MANTID_API_WORKSPACEUNITVALIDATORTEST_H_ */
-- 
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