When you you will receive an error :
“Invalid virtual machine configuration.”
While deleting or creating virtual machine snapshot you might have an issue with the snapshot dictionary file *.vmsd. To ensure that this is the case open the virtual machine log file (vmware.log), and browse through it. If you will see entries like:
DictionaryParseReadLine: syntax error with line, “.”.
SNAPSHOT: SnapshotConfigInfoReadEx: Unable to load dict from ‘/vmfs/volumes/xxx/VMfolder/VMname.vmsd’.
SNAPSHOT: SnapshotConfigInfoReadEx failed for file ‘VM.vmx’: Dictionary problem (6)
Then it might be the case where your vmsd file is not correct.
I found KB for this case . Basically you need to rename your vm.vmsd file to vm.vmsd.old file, and after that recreate it by creating new snapshot. Once this is done, go through vSphere client to the snapshot manager and use the ‘delete all’ button in order to get rid of all snapshots.
You also might want to double check your snapshot chain by reading the vmdk descriptors, and looking if parentCID/CID matches through the entire snapshot chain.
Don’t worry about the fact that in snapshot manager you can only see the snapshot you have just created. When you will click ‘delete all’ he will delete all snapshots in the chain. After this is completed, ensure that it was done by checking from which disk virtual machine is working and by reading vmsd file. Check if the directory does not contain any -00000 delta files.