Fix BSOD Error 0xc000021a in Windows 10

STOP c000021a {Fatal System Error}

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.

STOP c000021a {Fatal System Error}

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  • Corrupted, outdated or incompatible drivers

Fix BSOD Error 0xc000021a in Windows 10

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.

Press any key to boot from CD or DVD | Fix BSOD Error 0xc000021a in Windows 10

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

Repair your computer

4. On choose an option screen, click Troubleshoot.

Choose an option at windows 10 automatic startup repair

5. On Troubleshoot screen, click the Advanced option.

select advanced option from troubleshoot screen

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

run automatic repair | Fix BSOD Error 0xc000021a in Windows 10

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.

Repair your computer

6. On choose an option screen, click Troubleshoot.

Choose an option at windows 10

7. On Troubleshoot screen, click the Advanced option.

troubleshoot from choose an option | Fix BSOD Error 0xc000021a in Windows 10

8. On Advanced options screen, click Command Prompt.

Fix Driver Power State Failure open command prompt

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

10. Now type the following command:

BCDEDIT /SET {DEFAULT} BOOTMENUPOLICY LEGACY

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

Advanced boot options

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).

Boot into Last Known Good Configuration

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.

Repair your computer | Fix BSOD Error 0xc000021a in Windows 10

3. Now, choose Troubleshoot and then Advanced Options.

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

Restor your PC to fix system threat Exception Not Handled Error

5. Restart your PC to save changes.

Method 5: Run DISM Command

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

Fix Driver Power State Failure open command prompt

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

Dism /Online /Cleanup-Image /CheckHealth
Dism /Online /Cleanup-Image /ScanHealth
Dism /Online /Cleanup-Image /RestoreHealth

DISM restore health system

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:

Dism /Image:C:\offline /Cleanup-Image /RestoreHealth /Source:c:\test\mount\windows
Dism /Online /Cleanup-Image /RestoreHealth /Source:c:\test\mount\windows /LimitAccess

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.

Command prompt from advanced options | Fix BSOD Error 0xc000021a in Windows 10
2. At command prompt windows, type the following commands in order.

bcdedit -set loadoptions DISABLE_INTEGRITY_CHECKS
bcdedit -set TESTSIGNING ON

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:

bcdedit -set loadoptions ENABLE_INTEGRITY_CHECKS
bcdedit /set testsigning off

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.

Command prompt from advanced options

sfc /scannow
chkdsk C: /f /r /x

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.

run check disk chkdsk C: /f /r /x

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.

select refresh or reset your windows 10 | Fix BSOD Error 0xc000021a in Windows 10

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.

Posted by
Aditya Farrad

Aditya is a self-motivated information technology professional and has been a technology writer for the last 7 years. He covers Internet services, mobile, Windows, software, and How-to guides.

1 Comment

  1. I have tried every method on this page and nothing has worked so far*

    *In method 2 I do not get a “Last Known Good Configuration” displayed as an option from the boot menu.

    *Whenever I leave the Command Prompt screen there is no Restart option displayed as described. I am just returned to the previous troubleshooting menu with the Advanced option and Shutdown option. For all restarts I had to manually restart after shutting down and start the whole BSOD loop all over again.

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