Stop code: 0xc000021a - need advice

Light-Yagami · January 13, 2022

Hello everyone,

My laptop has done an overnight auto-update as it does every now and again, but this time, it was unsuccessful. That's what the code stands for: "unsuccessful windows update install". That puts the system into unusable state, and you can not boot into it. When you try to boot, it'll auto crash, and try to boot again - going into boot loop. I have safety measures in place. 2 bluescreens in a row, and it'll trigger an advanced repair window. I get a BitLocker prompt, which I can skip - but then it just tries to reboot, which it fails to do. So 48 numbers of BitLocker restore password later, the system restores itself to a safe state before the update, and boots normally.

I've manually disabled the windows update, but we all know that's not the long term solution. I have a few theories as to why this might happen, but also some counter arguments.

1. I have bios modded to allow for undervolting. 2 lines of code.

2. I had ThrottleStop running with custom profile

Counter agruments:

1. I've updated the bios many times since it was modded and it works just fine. It was updated at least 4 times after the mod.

2. I've run ThrottleStop for over a year, through many updates - never had any issues.

Is it possible that this is a faulty update? If this is something that's going to get fixed in the future, I'll just keep the update service disabled so it doesn't try and brick my laptop again.

The alternative is complete system reset, or at least that's what it seems after a brief google search. I can't imagine doing that, even if I keep all my files. I have numerous programs installed that I use every day, and it would take me a week to get it up and running again, possibly more.

If there are different solutions to this problem, please let me know. Anything might help. Thank you.

RTX 3071 · January 13, 2022

You can try the basic sfc and DISM commands for a scan and see if they find anything.

Light-Yagami · January 13, 2022

1 hour ago, RTX 3071 said:

You can try the basic sfc and DISM commands for a scan and see if they find anything.

Done that, no issues found

I've found on the web that some times, new cumulative updates fail to install if there isn't a specific windows update installed previously. Which in my case, it wasn't. Or at least I think. I'll have everything turned off for now, and manually install updates at a later date. Hopefully by then, problems will be fixed by intel and I won't need to reset the system. I have most auto updates disabled, maybe something didn't go through and I have issues now. We'll see.