VMWare is excellent for malware analysts because it lets you keep snapshots of pristine Virtual machine states and you can revert back to them when you want to.
I encountered a weired error this time around on my Windows XP Pro VM. Whenever I would try to take any snapshots I would get an error: “Error taking snapshot: Windows XP Professional.VMX-Snapshot1.vmsn file already exists”. When I looked into the folder there was no .vmsn file with that name. I deleted all the files .lck and .lock files and still to no avail. Then I saw the files named as
Windows XP Professional-000001-s00?.VMDK.
The regex for these files was:
Windows XP Professional-00000?-s00?.VMDK
where ? is one character replaced by 0-9. Upon deleting these files, my snapshots started working properly.