Sysprep – Fatal error occurred while trying to sysprep the machine

Setting HKEY_LOCAL_MACHINE\SYSTEM\Setup\Status\SysprepStatus to 7

Setting HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform\SkipRearm to 1

Renaming (or deleting) C:\Windows\System32\sysprep\Panther

 

Make sure to do all three each time you attempt a sysprep.