from https://forums.virtualbox.org/viewtopic.php?f=1&t=41293 You see this error message when trying to start a VM that has a .VHD disk and a snapshot: Parent UUID {00000000-0000-0000-0000-000000000000} of the medium '... .vdi}' does not match UUID {1b3b7ea8-... .vdi} of its parent medium stored in the media registry Solution: manually set the parent UUID field of the snapshot differencing disk. Find the snapshot disk file and do: vboxmanage internalcommands dumphd info : from the parent and the snapshot to get UUIDs vboxmanage internalcommands sethdparentuuid : to set the parent of the errant snapshot to the proper vhd