diff --git a/Framework/MDAlgorithms/src/ConvertToMD.cpp b/Framework/MDAlgorithms/src/ConvertToMD.cpp
index c080fa8ef87be8acc84f8ac2f9db5756f30e1179..90adc440b12e93a82c06ed6eda9871f501054801 100644
--- a/Framework/MDAlgorithms/src/ConvertToMD.cpp
+++ b/Framework/MDAlgorithms/src/ConvertToMD.cpp
@@ -378,7 +378,8 @@ void ConvertToMD::copyMetaData(API::IMDEventWorkspace_sptr &mdEventWS) const {
   auto mapping = boost::make_shared<det2group_map>();
   for (size_t i = 0; i < m_InWS2D->getNumberHistograms(); ++i) {
     const auto &dets = m_InWS2D->getSpectrum(i).getDetectorIDs();
-    mapping->emplace(*dets.begin(), dets);
+    if (!dets.empty())
+      mapping->emplace(*dets.begin(), dets);
   }
 
   // The last experiment info should always be the one that refers