Index: /trunk/src/VBox/Main/src-server/MachineImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/src-server/MachineImpl.cpp	(revision 37091)
+++ /trunk/src/VBox/Main/src-server/MachineImpl.cpp	(revision 37092)
@@ -9537,5 +9537,6 @@
             // unregistered images)
             Guid uuidRegistryParent;
-            Assert(pMedium->getFirstRegistryMachineId(uuidRegistryParent));
+            bool fInRegistry = pMedium->getFirstRegistryMachineId(uuidRegistryParent);
+            Assert(fInRegistry); NOREF(fInRegistry);
             rc = diff->init(mParent,
                             pMedium->getPreferredDiffFormat(),