diff --git a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/OSSL_Api.cs b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/OSSL_Api.cs
index 62cd75fc48..e3a750d531 100644
--- a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/OSSL_Api.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/OSSL_Api.cs
@@ -2106,6 +2106,9 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
 
         private LSL_Key NpcCreate(string firstname, string lastname, LSL_Vector position, string notecard, bool owned)
         {
+            if (!owned)
+                OSSL_Error("Unowned NPCs are unsupported");
+            
             string groupTitle = String.Empty;
 
             if (firstname != String.Empty || lastname != String.Empty)