Boot cycle BSOD 0xc0000021a. No fixes are working.

Hi all,

I am at my wits end with this. I am having the BSOD with error code 0xc0000021a. From what I have Google, this means the pc crashed during a windows update and now the boot process is corrupted.

I have to apologise as because I cannot boot the PC I cannot provide the files requested on the sticky. I am running 8.1 and have provided as much info as possible here. If there is a way of getting info you can use without booting windows, I'll get it no trouble.

I am by no means an expert at this, but my rig is a homebuild, and as such I have become somewhat capable of finding and implementing fixes to a whole range of issues and crashes (the Internet is my friend).

I have been able to find a good number of fixes for this, none of which work, including certain cmd prompt lines (chkdsk, sfc, and another one involving DISM and revertpendingactions).

The PC does enter the windows recovery environment, the blue screen with several repair options). I have tried the start up repair, with no luck, and cannot boot into any of the safemode options or other choices for reboots; they all bring me back to the original 21a error.

I have even got a recovery media USB from a friend and attempted a refresh, which fails as does any attempt at a system restore.

I think I've covered all the things I've tried. Last step is a full system restore, which I really want to avoid.

I am happy to repeat any of the things already tried, I just really want my pc back!

Thanks in advance,

Ollie

This article suggests cause was a bad NVidia driver update cause this person's blue-screen. Windows 8 pro BSOD 0xc000021a error - Microsoft Community
Did you do any updates? But you say you can't get into to Safe Mode - so you can't remove them, if you did.
You ran Sfc and Chkdsk. There's not much left to try.

Last step is to try a Refresh (no data lost) http://www.eightforums.com/tutorials/2293-refresh-windows-8-a.html
If that doesn't work than your only option (AFAIK) is to do a restore http://www.eightforums.com/tutorials/4692-system-restore-how-do-windows-8-a.html

Hi countrybumpkin thanks for the reply,

I read through that article and it is very similar, could be the same root cause however still no luck with fixes.
I have run through the steps in this article https://www.winhelp.us/repair-your-computer-in-windows-8.html#dismrevert but still have no luck!

I am attempting a refresh, but it tells me the drive where windows is installed is locked. Unlock and try again.
I have no idea what it means by locked.

It's looking more and more like I'm going to have to reset it.