diff --git a/MantidPlot/src/Mantid/MantidUI.cpp b/MantidPlot/src/Mantid/MantidUI.cpp
index a67ed40590ca12365844b06f30f9ab1317ab21da..f6fc450f085c72a4f4579bf2b31fcc5f8889c710 100644
--- a/MantidPlot/src/Mantid/MantidUI.cpp
+++ b/MantidPlot/src/Mantid/MantidUI.cpp
@@ -1270,6 +1270,11 @@ Table *MantidUI::createDetectorTable(
     const std::vector<int> &indices, bool include_data) {
   using namespace Mantid::Geometry;
 
+  IComponent_const_sptr sample = ws->getInstrument()->getSample();
+  if (!sample) {
+    return nullptr;
+  }
+
   // check if efixed value is available
   bool calcQ(true);
 
@@ -1330,7 +1335,6 @@ Table *MantidUI::createDetectorTable(
   t->setTextFormat(ncols - 1);
 
   // Cache some frequently used values
-  IComponent_const_sptr sample = ws->getInstrument()->getSample();
   const auto beamAxisIndex =
       ws->getInstrument()->getReferenceFrame()->pointingAlongBeam();
   const auto sampleDist = sample->getPos()[beamAxisIndex];
diff --git a/qt/widgets/common/src/WorkspacePresenter/WorkspaceTreeWidget.cpp b/qt/widgets/common/src/WorkspacePresenter/WorkspaceTreeWidget.cpp
index 9e08a44e462f97b068dab68b1b3c437ea8753aa5..7e0bb479cb329f963ec5adc936053b5c0030fa9d 100644
--- a/qt/widgets/common/src/WorkspacePresenter/WorkspaceTreeWidget.cpp
+++ b/qt/widgets/common/src/WorkspacePresenter/WorkspaceTreeWidget.cpp
@@ -1600,9 +1600,14 @@ void WorkspaceTreeWidget::onClickShowDetectorTable() {
 
 void WorkspaceTreeWidget::showDetectorsTable() {
   // get selected workspace
-  auto ws = getSelectedWorkspaceNames()[0];
-  m_mantidDisplayModel->createDetectorTable(QString::fromStdString(ws),
-                                            std::vector<int>(), false);
+  auto ws = QString::fromStdString(getSelectedWorkspaceNames()[0]);
+  auto table =
+      m_mantidDisplayModel->createDetectorTable(ws, std::vector<int>(), false);
+  if (!table) {
+    QMessageBox::information(
+        this, "Error",
+        QString("Cannot create detectors tables for workspace ") + ws);
+  }
 }
 
 void WorkspaceTreeWidget::onClickShowBoxData() {