Windows 10 1909 Update KB5004245 crashes bootloader?

Question

Dear Community,

lately I run into trouble updating my Windows 10 laptop:

Hardware: Dell Latitude 5400
OS Version: Windows 10 Enterprise, Version 1909 (Build 18363.1621)

Symptoms:
Auto-Update was enabled and all previous updates installed without issue. Whenever I try to install the cumulative July 2021 update KB5004245, it appears as if the bootloader gets corrputed.

After the required restart, I get a BSOD:
"Recovery
Your PC/Device needs to be repaired
The application or operating system couldn't be loaded because a required file is missing or contains errors.

File: \Windows\system32\winload.efi
Error code: 0xc000007b"

Preliminary Fix
To fix this I booted from Windows 10 installation USB stick and initially followed the instructions from Dell to recover the bootloader ( bootrec /FixBoot) but this results in "Access Denied" message.

Using different instructions based on formatting the boot partition and repairing the bootloader with the command bcdboot successfully fixes the bootloader but the update fails to install.

In the update history i find the error code 0x800f0845

I have also tried to install the 20H2 version instead, but this resulted in similar errors which I was not able to fix and therefore recovered the whole installation from a previous disk image.

Question
Does someone experience similar problems, or may assist me in pinpointing the source of error? Your help is very much appreciated.

Kind regards,
Max

Answer 1

Hi Max,

Please try the latest 21H1 version, on my 21H1 computer, the July 13, 2021 update KB5004237 installed successfully and doesn’t lead to BCD or bootloader issue, you could have a try.

Use Windows Update Assistant or Media creation tool to upgrade to this version.
https://www.microsoft.com/en-us/software-download/windows10

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Answer 2

Thank you @Teemo Tang for the suggestion.

Interestingly using the Windows Update Assistant for the latest feature update 21H1 did not work as expected: After downloading and installing the update, I was requested to restart my PC. After reboot there was no message altogether regarding the update, but my Windows version remained at 1909.

Luckily the bootloader crash seems to be resolved in a different way: I postponed updates until the August 2021 cumulative update was available (KB5005031) and this one worked perfectly without getting any errors.

When I find the time to retest 20H2, I will let you know the results.