diff --git a/pcbnew/dialogs/dialog_drc.cpp b/pcbnew/dialogs/dialog_drc.cpp
index b654328eba..c2e7272539 100644
--- a/pcbnew/dialogs/dialog_drc.cpp
+++ b/pcbnew/dialogs/dialog_drc.cpp
@@ -401,7 +401,7 @@ void DIALOG_DRC::OnDRCItemSelected( wxDataViewEvent& aEvent )
                 LSET layersList = getActiveLayers( it );
                 violationLayers &= layersList;
 
-                if( principalLayer <= UNDEFINED_LAYER )
+                if( principalLayer <= UNDEFINED_LAYER && layersList.count() )
                     principalLayer = layersList.Seq().front();
             }
         }