diff --git a/OpenRA.Game/Traits/World/ActorMap.cs b/OpenRA.Game/Traits/World/ActorMap.cs
index 4df7cf2d48..1a43bc291d 100644
--- a/OpenRA.Game/Traits/World/ActorMap.cs
+++ b/OpenRA.Game/Traits/World/ActorMap.cs
@@ -150,8 +150,9 @@ namespace OpenRA.Traits
 
 			public void Dispose()
 			{
-				foreach (var a in currentActors)
-					onActorExited(a);
+				if (onActorExited != null)
+					foreach (var a in currentActors)
+						onActorExited(a);
 			}
 		}