Unmountable_Boot_Volume stop message after upgrading
A user tries to upgrade his Windows Vista computer to Windows 7. During the installation process, after the reboot, the following stop message is displayed:
The problem was this: the user had previously encrypted the boot/system volume on his computer using a third-party full-disk encryption program. The problem is that he didn't decrypt the volume before starting the upgrade.
Make sure you decrypt encrypted system/boot volumes on Windows Vista computers before upgrading them to Windows 7.