My adventure of fixing Windows 10 boot issues

Ventoy to the rescue to repair Windows 10

Since my early days with computers, friends and family have asked me for advice and to "take a look" at their current IT issues. Recently, a neighbor contacted me with a tough problem. A tower PC with Windows 10, which had been in use for 10 years and had many to him valuable programs installed, had crashed and could no longer be started. The recovery screen did not make any sense to him. My quick Internet search indicated that most advise centered around reinstalling Windows or getting a sledge hammer...

Windows boots in safe mode only

First tests show that the computer can only start Windows 10 in safe mode. Any other attempts result in some failure followed by an automatic restart. Pressing the power button during restart speeds up the "cycle of no hope". The safe mode offers an automatic startup repair, but results in the "could not repair" message. Fortunately, disk checks indicate that the data is well.

All attempts to repair the Windows Boot Manager and / or the Master Boot Record (MBR) fail, either due to insufficient authorization, non-existance of tools recommended on the Microsoft community pages, or by inflicting new problems.

Ventoy to the resuce

The next attempt to repair the Windows system was to start an update or new installation from a recovery medium or to boot into Windows from USB. For that, I prepared a USB flash drive with Ventoy as base. It allowed me to pick from different operating system images, including Windows 10, gparted, and Linux. But all attempts failed again because it either would have meant to wipe out everything or the installer / updater could not be started due to a variety of errors.

Starting some Linux tools only helped in that sense to verify that the core system and its data was ok.

bcdboot it is!

What helped at last, was to boot into the safe mode again and to open the Windows command prompt as administrator. Instead of using the command bcdboot to create new entries in the boot file, I simply ran:

bcdboot /bcdclean

The option is shown in the tool help, but not really documented (IMHO). After running the command, I shut down the system and started it again ("Have you tried turning it off and on again?"). Some flashes plus messages about reconfiguration and repairs later, the regular welcome screen with the login prompt appeared. Repeated restarts and logins showed that the machine was repaired, no data lost.

Never give up (or not too soon...)

The above experience showed me again not to give up too early and to try out different options while preserving the data.

That's it for today. If you have feedback, suggestions, or questions about this post, please reach out to me on Mastodon (@data_henrik@mastodon.social) or LinkedIn.