I am having the same issue and it is very fruuuustrating to have it pop up and not continue. I have tried and looked at several different styles of [unattended] commands and found no resolve. I am surprised to see you using 'UnattendMode=FullUnattended' and still seeing that failure point. I wish I could help out more. Here is what I am using with the same problem. [Unattended] UnattendMode=DefaultHide UnattendSwitch=Yes OemSkipEula=Yes OemPreinstall=Yes WaitForReboot = No NoWaitAfterTextMode = 1 NoWaitAfterGUIMode = 1 TargetPath=\WINDOWS Repartion=Yes AutoActivate=YES DriverSigningPolicy=Ignore OemPnPDriversPath="drivers\"