Index: DamEngine/trunk/src/Deltares.DamEngine.Interface/EngineInterface.cs
===================================================================
diff -u -r6774 -r6775
--- DamEngine/trunk/src/Deltares.DamEngine.Interface/EngineInterface.cs	(.../EngineInterface.cs)	(revision 6774)
+++ DamEngine/trunk/src/Deltares.DamEngine.Interface/EngineInterface.cs	(.../EngineInterface.cs)	(revision 6775)
@@ -115,7 +115,6 @@
             MessageType = LogMessageType.Info,
             Message = Resources.StartValidation
         });
-        List<LogMessage> validationMessages = null;
 
         try
         {
@@ -133,18 +132,8 @@
             }
         }
 
-        // Local validation can give messages and these have to be added to the results but note that there
-        // already can be messages added by instantiation of the interface too. So add the local to the global
-        if (validationMessages != null && validationMessages.Count > 0)
-        {
-            if (DamProjectData != null && DamProjectData.CalculationMessages != null)
-            {
-                DamProjectData.CalculationMessages.AddRange(validationMessages);
-            }
-        }
-
         // Now check if there are any messages at all, if so return them.
-        if (DamProjectData != null && DamProjectData.CalculationMessages != null && DamProjectData.CalculationMessages.Count > 0)
+        if (DamProjectData is { CalculationMessages.Count: > 0 })
         {
             Output output = FillXmlOutputFromDam.CreateOutput(DamProjectData);
             string outputXml = DamXmlSerialization.SaveOutputAsXmlString(output);