HOWTO restore inaccessible boot disks

A day before Christmas, a friend of mine called me telling me that one of his notebook didn’t start anymore.

A glorious BlueScreen pops up giving an error 0xC000000E because a device isn’t accessible anymore.

We downloaded the latest Windows 10 Media Creation Tool to create a bootable USB Windows 10 image from where to try to fix the problem.  Naturally, the automatic recovery didn’t work.

After few investigations, we have to use the recovery console to try the following command sequence:

bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd

But the second command failed with ‘Access Denied’.  I tried to reboot, but the problem was still there.

After another investigation, it seems that we had to reset the ‘boot’ partition.

Resetting the boot partition

Always using the recovery console, type the following:

list disk
select disk <system disk number, usually 0>
list partition

Here it is essential to detect the boot partition from the list shown because it is the one that we will wipe out (ie wrong partition == data loss).
Usually, it is one with type set to ‘system‘, using Fat32 file system, and large few megabytes (100-300mb…).

select partition <system partition number>
format quick fs=fat32
list volume <to detect the proper volume 'letter', usually 'c'>

bcdboot <your Windows folder, usually 'c:\windows'>

After a reboot, the problem was fixed.