HELP! KB 60209 broke my system -- Windows won't start
So I carefully followed each and every step of KB 60209, for the purpose of testing the bootability of a disk image. I did get the UEFI warning, but the KB article says this can safely be ignored.
I successfully booted into the VHDX once, then restarted the computer. Now, the computer no longer boots at all (it hangs at the black "Dell" logo screen with the rotating dots). The only thing I have figured out is that going into startup repair and selecting Advanced Options, I can select "Other operating systems" which takes me to the bootloader. Here I can again boot into the VHDX, but if I select the native Windows 10 OS to boot into, it just hangs again and will not complete booting.
The KB article did provide instructions for backing up the bootloader settings in EasyBCD, which I had done, but the VHDX does not have EasyBCD installed. Should I install EasyBCD in the VHDX virtual operating system and then try to restore my original bootloader settings from here? Or will that make it worse?
I need advice urgently -- the KB article did not provide sufficient or accurate information for how to get your computer back to its original state. Help!