I have created a Vista disk image with ImageX, largely following the instructions at http://www.svrops.com/svrops/articles/sysprepvista.htm. When I apply the image to a clean, active partition on identical hardware, I get the message "BOOTMGR is missing."
I can get the computers to boot by using the repair tool on the Vista media. If I click "Repair your computer" after booting to the OS media, Windows searches for installations, presumably finds one, and says "Windows found problems with your computer's startup options." I then still get the "BOOTMGR is missing" error - but if I run the "Repair your computer" tool again, I get a dialog that allows me to choose "Startup repair" from a bunch of options. After this, the computer will boot.
I want to understand why this is happening - and how I can avoid it, either by adding script actions after the ImageX command or otherwise.