Index: /trunk/src/VBox/ValidationKit/tests/storage/tdStorageSnapshotMerging1.py
===================================================================
--- /trunk/src/VBox/ValidationKit/tests/storage/tdStorageSnapshotMerging1.py	(revision 78122)
+++ /trunk/src/VBox/ValidationKit/tests/storage/tdStorageSnapshotMerging1.py	(revision 78123)
@@ -183,6 +183,10 @@
         oVM = oSnapshot.machine;
         oMedium = self.getMedium(oVM, sController);
-
-        for oChildMedium in oMedium.children:
+        
+        aoMediumChildren = self.oVBoxMgr.getArray(oMedium, 'children')
+        if aoMediumChildren is None or len(aoMediumChildren) < 1:
+            return None;
+
+        for oChildMedium in aoMediumChildren:
             for uSnapshotId in oChildMedium.getSnapshotIds(oVM.id):
                 if uSnapshotId == oVM.id: