While sysprepping my golden image for my VDI collection I got this error:
Use this command to check: slmgr /dlv
Once I checked the log (C:\Windows\System32\sysprep\Panther\seterr.log) it mentioned Microsoft Security Essentials, which I had removed from the image since the last sysprep.
Thanks to this blog, it turns out that there was some old MSSE information left in the registry
This needed to be deleted (although the permissions at the level has to fist be changed to allow me to delete the key)
Once done the sysprep ran fine.