Edit: It seems like my issue was a VMWare Server bug, as when I had a chance to try it on a real box, the problem did not occur. Thanks again to those who assisted. ------------------- I've prepared a master image with the following HAL: Advanced Configuration and Power Interface (ACPI) PC - ACPIPIC_UP Then, on the target machine, I boot into WinPE, pull down the image, and modify sysprep.inf to use the appropriate HAL. I reboot, sysprep completes the mini-setup wizard and initiates another restart. The system fails to boot the OS at this point... however, if I physically reset at this point, it comes up with "Windows Failed to Start Something Something..." I select Boot Normally and the system boots fine. I log in and see that the correct HAL is being used. So for some reason the first time it boots after mini-setup completes, it is failing. The next and subsequent times it boots fine. Has anyone seen this before? If I take out the HAL update lines (UpdateUPHAL or UpdateHAL) this doesn't happen, so it must be due to the HAL replacement. It also does not seem to happen when the master image is a ACPI Multiprocessor HAL and I change to ACPI Uniprocessor HAL. Any ideas? Also, I'm using the -pnp switch when I run sysprep if that matters. Thanks for any help or ideas!