diff --git a/docs/source/release/v5.0.0/mantidplot.rst b/docs/source/release/v5.0.0/mantidplot.rst
index 8eea849e5303b482318cba617aa61e4cc92fd40c..59641d2dbbe595eac98453ad208cb2ac7e2a462a 100644
--- a/docs/source/release/v5.0.0/mantidplot.rst
+++ b/docs/source/release/v5.0.0/mantidplot.rst
@@ -15,6 +15,7 @@ Bugfixes
 - Fixed an issue where adding specific functions to the multi-dataset fitting interface caused it to crash
 - Fixed an issue where mantid crashed if you cleared the functions in the multi-dataset fitting interface
 - Fixed an issue where adding a UserFunction to the multi-dataset fitting interface caused a crash
+- Fixed an issue in the multi-dataset fitting interface where it crashed when doing a sequential fit with one spectra.
 
 
 :ref:`Release 5.0.0 <v5.0.0>`
\ No newline at end of file
diff --git a/qt/scientific_interfaces/MultiDatasetFit/MultiDatasetFit.cpp b/qt/scientific_interfaces/MultiDatasetFit/MultiDatasetFit.cpp
index ed4713ff7878fc58d46a7e5ecec6e2c86296c781..80f8ef20b043a7b5c8b98acb852489285bc7c562 100644
--- a/qt/scientific_interfaces/MultiDatasetFit/MultiDatasetFit.cpp
+++ b/qt/scientific_interfaces/MultiDatasetFit/MultiDatasetFit.cpp
@@ -496,7 +496,8 @@ void MultiDatasetFit::finishFit(bool error) {
     Mantid::API::IFunction_sptr fun;
     auto algorithm = m_fitRunner->getAlgorithm();
     if (m_fitOptionsBrowser->getCurrentFittingType() ==
-        MantidWidgets::FitOptionsBrowser::Simultaneous) {
+            MantidWidgets::FitOptionsBrowser::Simultaneous ||
+        getNumberOfSpectra() == 1) {
       // After a simultaneous fit
       fun = algorithm->getProperty("Function");
       updateParameters(*fun);