diff --git a/src/RhinoInside.Revit.GH/Components/TransactionalComponent.cs b/src/RhinoInside.Revit.GH/Components/TransactionalComponent.cs
index 6b43fc197..b815a1bdd 100644
--- a/src/RhinoInside.Revit.GH/Components/TransactionalComponent.cs
+++ b/src/RhinoInside.Revit.GH/Components/TransactionalComponent.cs
@@ -76,7 +76,7 @@ void AddRuntimeMessage(ARDB.FailureMessageAccessor error, bool? solved = null)
         return;
       }
 
-      if (severity == ARDB.FailureSeverity.Warning && FailureDefinitionIdsToFix.Contains(failureId))
+      if (severity == ARDB.FailureSeverity.Warning && FailureDefinitionIdsToFix?.Contains(failureId) is true)
         return;
 
       var level = GH_RuntimeMessageLevel.Remark;