diff --git a/MapoDb/DataLayer.cs b/MapoDb/DataLayer.cs
index f611fc38..0c08290d 100644
--- a/MapoDb/DataLayer.cs
+++ b/MapoDb/DataLayer.cs
@@ -477,7 +477,7 @@ namespace MapoDb
         /// <returns></returns>
         public static string ConfYamlHash(string idxMacchina)
         {
-            return mHash($"ConfYaml:{idxMacchina}");
+            return mHash($"IOB:{idxMacchina}:ConfYaml");
         }
 
         /// <summary>