When you run the Sysprep command on a Windows Vista-based computer, you receive an error message that resembles the following:

A fatal error occurred while trying to sysprep the machine

Additionally, an error code that resembles the following is logged in the Setupact.log file:

0×80070020
ERROR_SHARING_VIOLATION

Note: The Setupact.log file is located along the following path:
C:\Windows\Panther\Setupact.log