Recently we are extensively test a Horizon View 6 in a combination with the migration of workstations to Windows 8. Start and configure the first machine took an awfully long time. In the end I ran the console and was surprised to read the following message: Windows could not parse or process the unattend answer file for pass [specialize]. The settings specified in the answer file can not be applied. The error was detected while processing settings for component [Microsoft-Windows-Shell-Setup]. Restart of the machine did not help.
Quick search for a solution on the Internet led me to the conclusion, that used Windows key is invalid. After checking, I was found that in a hurry typed KMS key instead of MAK (LAB do not have KMS server). Fixed profile, destroy vm, and another machine is personalized properly.