The stop code 0xc000021a represents the WINLOGON_FATAL_ERROR, which occurs when a user-mode subsystem, such as WinLogon or Client Server Run-Time Subsystem (CSRSS), is compromised. It additionally means that security can’t be guaranteed for your system due to this error. And in turn, the Windows Operating System (OS) switches to the kernel-mode, showing a blue screen.
Sometimes, when you restore your hard disk from a backup, the system files can be corrupted or faulty and may cause this error on your system. Other causes behind the 0xc000021a error may include a corrupted hard drive, faulty device drivers, incompatible software/app installed, and problematic Windows update.
Here I am sharing with you some of the methods that you can use :
How to fix the 0xc000021a error code?
Run SFC Tool
Run Windows Defender Antivirus Tool
Update/Uninstall Device Driver
Uninstall Problematic Windows Update
Run CHKDSK Command
Uninstall Incompatible Software/Application
Perform System Restore
To enter Safe Mode, follow the given steps:
Restart your system; as soon as you see the Windows logo on the screen, reboot it again and repeat this step thrice.
After that, you’d reach the Automatic Repair environment.
There, click ‘Advanced options’, leading you to the ‘Choose an option’ screen.
There, click Troubleshoot > Advanced options > Startup Settings > Restart.
Once your system gets restarted, click F4 to enable Safe Boot.
Method 1: Run SFC Utility
Press Windows + R to open the Run dialog box.
Open Command Prompt and choose to run it as administrator.
Then type the following command and press Enter.
Now, wait for a while as it may take some time to show system files that need to be fixed.
Next, type SFC/scannow command and hit Enter.
Let the process complete. Once done, close the window and try rebooting your system to check if the error is gone.
Method 2: Run Windows Defender Antivirus Tool
Open System Settings and go to Update & Security > Windows Security > Virus & threat protection.
The Windows built-in Windows Defender antivirus program will start scanning the PC for any viruses. If there’s a malware present on your system, it will show up in the results.
Next, follow the instructions given on the screen to fix the windows stop code 0xc000021a. After completion, reboot your system and check if the problem is solved.
Method 3: Update/Uninstall Device Driver
Press Windows + X, click Device Manager and then navigate to the device category where you want to update the drivers.
Expand the device category and right-click on the driver. Choose Update driver.
Next, choose to ‘Search automatically for updated driver software.’
Let Windows look for the latest driver software available.
If you already have the latest driver, try uninstalling it and then re-installing it with the compatible one.
Go to the device driver, which seems to be causing the issue, and right-click on it.
Choose Uninstall device.
On the next prompt, click ‘Delete the driver software for this device’ and click Uninstall.
Wait and let the process end. Now, close the window and check if the error is gone. Afterward, you can download the compatible device driver by visiting their manufacturer’s site.
Hope all these steps will help you out