During these days a faced following problem.
On vmware there was a VM that had various vmdk files that was indicating more snapshot available.
Searching on vSphere client there was not possibility to revert to them ore delete old snapshots.
Solution was to create a new snapshot and then delete it immediately.
Following this procedure all old snapshot was succesfully deleted.
Here is original Vmware article:
Committing snapshots when there are no snapshot entries in the Snapshot Manager (1002310)
https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1002310
