Help Needed

TaskbarTactician

I’ve been encountering the 0xc00021a error code when trying to start my PC and I could really use some help. The error message pops up almost immediately when I try booting into Windows, and I’m not sure what’s causing it. From what I’ve gathered, it seems to be a critical system error linked to the Winlogon or CSRSS processes.

Has anyone else encountered this issue before? If so, what did you do to fix it? I’ve tried booting into Safe Mode, but the same error appears. I also attempted to use the automatic repair tool in the Windows boot options, but it didn’t resolve the issue.

I’m not sure if it’s a software or hardware problem, so any advice or steps to troubleshoot this would be greatly appreciated! Thanks in advance for your help!

processmonitor

The 0xc00021a error can indeed be tricky since it involves critical system processes. If Safe Mode and the automatic repair tool haven’t worked, here are a couple more things you might try:

System Restore: If you have a restore point from before the issue started, boot into the Windows Recovery Environment (maybe from a USB or installation disc) and try rolling back to that restore point.
CHKDSK and SFC: Run check disk (chkdsk) and system file checker (sfc /scannow) from the command prompt in the recovery environment to check for and fix potential corruption on your disk and system files.
Driver Issues: Sometimes it’s caused by a faulty driver. If you’ve recently updated a driver, see if you can boot into the last known good configuration or attempt rolling back any recent driver updates.
Hardware Check: Since the error persists in Safe Mode, make sure to rule out hardware issues like faulty RAM or a failing hard drive. Tools like MemTest86 for RAM and manufacturer’s diagnostics for the hard drive can help.

These steps should provide more insight into whether the issue is software or hardware-related. Keep us posted on your progress!