Index: /trunk/src/VBox/Storage/VD.cpp
===================================================================
--- /trunk/src/VBox/Storage/VD.cpp	(revision 66486)
+++ /trunk/src/VBox/Storage/VD.cpp	(revision 66487)
@@ -8810,4 +8810,6 @@
             pImage->Backend->pfnRegionListRelease(pImage->pBackendData, pRegionList);
         }
+        else
+            cbSector = 0;
     } while (0);