diff --git a/contrib/src/ai/aiBehaviors.cxx b/contrib/src/ai/aiBehaviors.cxx
index b5a4e4b5a8..da17488c8d 100644
--- a/contrib/src/ai/aiBehaviors.cxx
+++ b/contrib/src/ai/aiBehaviors.cxx
@@ -1184,6 +1184,7 @@ string AIBehaviors::behavior_status(string ai_type) {
 
       default:
         cout<<"Invalid value!"<<endl;
+        return "invalid";
     }
   }