There may come a day when you need to rebuild the boot partition. In my case took a Disk2VHD capture of a laptop and it would not boot when I hooked it up to Hyper-V. The following got me running.
Rebuilding the boot partition
Boot into a Windows installation disk and select Repair your computer
Now select Troubleshoot
Then Command Prompt
1 diskpart 2 list vol 3 sel volume 3 4 assign letter=L: 5 exit 6 L: 7 format L: /fs:fat32 8 bcdboot c:\windows /s L: /f UEFI 9 exit
Note: In this example I selected Volume 3. This may not always be the correct volume in all cases. Usually the volume you are looking for it the smallest on the drive.
Now you can select Continue or Turn off your PC
Hopefully, now your device can boot