If you’ve searched for 0xC000021A, chances are you’ve recently started your computer after some updates have “applied” and you’ve been greeted with a stupid blue screen with 0xC000021A and now you’re stuck in a boot loop. Yeah?
This is because of Windows Update, for some reason an update has broken something and caused a problem with the Windows boot process. I’m fairly certain this update is a specific one, possibly for Windows 8.1 Pro as this issue occurred on my main PC and also Surface Pro 3 but not my laptop – yet. Anyway, thankfully it’s a relatively simple fix.
Remember that recovery disk you made? You’ll need that, or because I don’t know many people who have a recovery disk, you’ll need a Windows 8.1 CD or another Windows 8.1 computer and a free USB drive.