The dark truth

Today we learned that Quickprep does not generate a new machine SID (Yes, it IS in the manual), so quickprep'ing 25 VM's won't activate a KMS server. Nice, I had to create a Sysprep'd pool just to trigger KMS...
The worse thing, that sometimes recomposing simply fails because of some kind of AD error etc.
If this happens, You've to manually clean out the failed VM. This is tricky, see http://kb.vmware.com/kb/1008658. You have to run a SviConfig -operation=removesviclone command on the view composer (vCenter) machine, and manually remove the ADAM CN from the View manager. This is done in ADSI edit, as stated in the KB above.
The trick is, sometimes this is not enough. Looks like the clone vanished, in AD Users and Computers mmc snap-in You don't see the incriminated computer's name, but View manager fails to create the VM again, because it still sees it in AD ("A computer with the name xxx already exists in Active Directory.") . Now, this happens when AD does not really delete the computer's account. To circumvent this, You manually recreate a computer account name with the same name as the VM, and delete it again...
Sorry, late night post.