Fix BSOD Error 0xc000021a in Windows 10

Error 0xc000021a is a Blue Screen of Death (BSOD) error which occurs randomly on your PC and states that “Your PC ran into a problem and needs to restart.” It’s possible that even after a restart you may not be able to access your PC. The error 0xc000021a occurs when the WinLogon (Winlogon.exe) or Client Server-Run Time Subsystem (Csrss.exe) files are damaged. Winlogon is responsible for handling the login and logout processes and Client Server-Run Time Subsystem belongs to Microsoft Client or Server. If these two files are damaged, then you will see the error message:

STOP: c000021a {Fatal System Error}
The Windows subsystem system process terminated unexpectedly with a status of 0xc0000005.
The system has been shut down.

Also, the error seems to occur because of the following number of reasons:

  • System Files are damaged.
  • Incompatible 3rd party Software
  • Corrupted, outdated or incompatible drivers

Now that you are aware of what causes the BSOD error 0xc000021a let’s see how to actually Fix BSOD Error 0xc000021a in Windows 10 with the below-listed troubleshooting steps.

Note: Make sure you have Windows Installation or Recovery Disc before continuing.

Fix BSOD Error 0xc000021a in Windows 10

If on Windows 10 then Enable Legacy Advanced Boot Options Screen.

Method 1: Run Startup/Automatic Repair

1. Insert the Windows 10 bootable installation DVD and restart your PC.

2. When prompted to Press any key to boot from CD or DVD, press any key to continue.

3. Select your language preferences, and click Next. Click Repair your computer in the bottom-left.

4. On choose an option screen, click Troubleshoot.

5. On Troubleshoot screen, click the Advanced option.

6. On the Advanced options screen, click Automatic Repair or Startup Repair.

7. Wait till the Windows Automatic/Startup Repairs complete.

8. Restart and you have successfully Fix BSOD Error 0xc000021a in Windows 10, if not, continue.

Also Read: How to fix Automatic Repair couldn’t repair your PC.

Method 2: Boot into Last Known Good Configuration

Before going any further let’s discuss how to Enable Legacy Advanced Boot Menu so that you can easily get Boot Options:

1. Restart your Windows 10.

2. As the system restarts enter into BIOS setup and configure your PC to boot from CD/DVD.

3. Insert the Windows 10 bootable installation DVD and restart your PC.

4. When prompted to Press any key to boot from CD or DVD, press any key to continue.

5. Select your language preferences, and click Next. Click Repair your computer in the bottom-left.

6. On choose an option screen, click Troubleshoot.

7. On Troubleshoot screen, click the Advanced option.

8. On Advanced options screen, click Command Prompt.

9. When the Command Prompt(CMD) open type C: and hit enter.

10. Now type the following command:

11. And hit enter to Enable Legacy Advanced Boot Menu.

12. Close Command Prompt and back on the Choose an option screen, click Continue to restart Windows 10.

13. Finally, don’t forget to eject your Windows 10 installation DVD to get Boot options.

14. On the Boot Options screen, choose  “Last Known Good Configuration (Advanced).

This would Fix BSOD Error 0xc000021a in Windows 10, if not then continue with the next method.

Method 3: Uninstall 3rd party software in Safe Mode

Using the above guide from the Advanced boot option, select Safe Mode then uninstalls any 3rd party software that might be conflicting with Windows.

Method 4: Run System Restore

1. Put in the Windows installation media or Recovery Drive/System Repair Disc and select your language preferences, and click Next

2. Click Repair your computer at the bottom.

3. Now, choose Troubleshoot and then Advanced Options.

4. Finally, click on “System Restore” and follow on-screen instructions to complete the restore.

5. Restart your PC to save changes.

Method 5: Run DISM Command

1. Again open the Command Prompt from the above-specified method.

2. Type the following command in cmd and hit enter after each one:

3. Let the DISM command run and wait for it to finish.

4. If the above command doesn’t work, then try on the below:

Note: Replace the C:\RepairSource\Windows with your repair source (Windows Installation or Recovery Disc).

5. Reboot your PC to save changes, and this should Fix BSOD Error 0xc000021a in Windows 10.

Method 6: Disable Driver Signature Enforcement

1. Again open an elevated command prompt from the above method.

2. At command prompt windows, type the following commands in order.

3. Reboot your computer and see if you’re able to Fix BSOD Error 0xc000021a in Windows 10.

Note: If you want to enable signature enforcement in the future, then open Command Prompt (with administrative rights) and type these commands in order:

Method 7: Run SFC and CHKDSK

1. Again go to command prompt using the method 1, click on command prompt in the Advanced options screen.

Note: Make sure you use the drive letter where Windows is currently installed. Also in the above command C: is the drive on which we want to check disk, /f stands for a flag which chkdsk the permission to fix any errors associated with the drive, /r let chkdsk search for bad sectors and perform recovery and /x instructs the check disk to dismount the drive before beginning the process.

3. Exit the command prompt and restart your PC.

Method 8: Refresh or Reset Your PC

1. Choose Troubleshooting when the Boot menu appears.

2. Now choose between the option Refresh or Reset.

3. Follow the on-screen instructions to complete the Reset or Refresh.

4. Make sure you have the latest OS disc (preferably Windows 10) to complete this process.

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That’s it you have successfully Fix BSOD Error 0xc000021a in Windows 10 but if you still have any questions regarding this post then feel free to ask them in the comment’s section.