Index: DamEngine/trunk/src/Deltares.DamEngine.Data/Standard/ObjectExtensions.cs
===================================================================
diff -u -r4540 -r5460
--- DamEngine/trunk/src/Deltares.DamEngine.Data/Standard/ObjectExtensions.cs	(.../ObjectExtensions.cs)	(revision 4540)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data/Standard/ObjectExtensions.cs	(.../ObjectExtensions.cs)	(revision 5460)
@@ -270,8 +270,8 @@
     /// <param name="excludedProperties"></param>  
     public static void CloneProperties<T1, T2>(this T1 origin, T2 destination, params string[] excludedProperties)
     {
-        // Instantiate if necessary  
-        if (destination == null)
+        // Destination must be instantiated  
+        if (destination.Equals(default(T2)))
         {
             throw new ArgumentNullException("destination", "Destination object must first be instantiated.");
         }