Just discovered that if you use EWF Disk Overlay mode and set the disk overlay size (in TD) to something very small (by default it is only 1024Kb) you are going to get the UNMOUNTABLE_BOOT_DISK BSOD (Blue Screen of Death) right after the second reboot after you enabled the EWF.
The reason is, probably, that when you enable EWF and reboot (to take the change in affect) the OS starts redirecting all the disk writes to the Disk overlay. It is trying to but obviously the size of the overlay (the size of the hidden partition that holds that Disk overlay) is not enough to cover all the changes, even unintentional ones like underlying system logs, changes to registry hives, etc. Somehow EWF doesn't give you any notifications about it (and that may make sense on a headless embedded devices, btw). At the next boot the disk writes saved in the overlay are validated and this leads to the BSOD.
It is actually easy to prove that it is the EWF (not corrupted FS or etc.) that is the cause fot the BSOD. Just open up the system registry hive of the crashed image offline (from another OS load such as XP Pro or WinPE) and remove the EWF from the list of volume upper filters for the disk driver. You will be able to boot the "patched" image just fine.
Another way to prove that is to delete the EWF hidden partition that holds the broken overlay. Obviously, EWF will become useless after that but you can always get it back to the default working state by issuing the following command "rundll32 ewfdll.dll, ConfigureEwf" that will re-create and initialize the EWF config (overlay) partition on the disk.