Index: /trunk/src/VBox/Main/MachineImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/MachineImpl.cpp	(revision 26192)
+++ /trunk/src/VBox/Main/MachineImpl.cpp	(revision 26193)
@@ -3339,6 +3339,7 @@
     Guid uuid(aId);
     /* Todo: fix this properly by perhaps introducing an isValid method for the Guid class */
-    if (    aId
-        &&  uuid.isEmpty())
+    if (    (aId)
+        &&  (*aId != '\0')      // an empty Bstr means "get root snapshot", so don't fail on that
+        &&  (uuid.isEmpty()))
     {
         RTUUID uuidTemp;