Error 0xc000021a appears in Windows 10 after the upgrade. It may also occur after doing a repair install.
Error 0xC000021A can occur if Winlogon.exe or Csrss.exe stops working. This happens if:
- There have been corrupt system files on the computer.
- There has been an unsuccessful upgrade.
- Incomplete software installation.
How to fix error 0xc000021a in Windows 10
Here are some ways to fix error 0xc000021a in Windows 10:
Start Windows 10 In Safe Mode
You should automatically see the boot repair screen if your computer reboots because of the blue screen error. You can also access these options by starting your computer with a Windows 10 disc or bootable USB disk.
If you are booting from the disc, be sure to click Repair your computer.
Click Troubleshoot > Advanced Options
Click Startup Settings > Restart
You can choose how to start Windows in Safe Mode by selecting one of the options available when the computer restarts. It would be best if you tried turning on Safe Mode with Networking so you can use the internet in safe mode. Suppose safe mode does not load in this mode, select simple safe way, number 4 in the list below.
Starting your computer in safe mode allows you to copy important data and run commands to fix the problem. You can try using the sfc / scannow command in the command prompt window to scan and repair corrupted system files on the computer.
Reset Windows 10
You can also try to refresh Windows 10 using a Windows 10 pre-installed DVD or USB. Click Repair your computer > Troubleshoot > Reset this PC.
This will remove all installed software and user accounts from the Windows partition and reinstall Windows.
Is your computer healthy?
I always recommend that every reader regularly use a reliable registry cleaner and optimizer like WinThruster or CCleaner. Many problems that you encounter can be attributed to a corrupt and bloated registry.