How To Easily Fix The BSOD Error 0xc000021a On Windows 10

When Windows 10 was release it had quite a few bugs, one of which caused a blue screen of death which shows the error 0xc000021a at the bottom of the screen. The error says that your PC ran into a problem and needs to restart. This error appears every time you restart your machine, You can not boot your machine to the windows 10 desktop.  Sometime a full system restore does not resolve this issue.



Cause Of 0xc000021a BSOD On Windows 10

The error 0xc000021a usually appears on a microsoft windows 10 machine after upgrading from a previous version of microsoft windows or after running a repair installation. When you get the blue screen of death the below will show on your screen.


When you get this error it is usually caused by an issue with one of two files.

  • Winlogon.exe - This file handles the logon and log off process when you get to the windows 10 desktop. This file could of been deleted, damaged, corrupted or has been replaced by a 3rd party software.
  • csrss.exe - This file is a core operating system file that handles the graphical instruction of the windows 10 system. Again this file could of been deleted, damaged, corrupted or has been replaced by a 3rd party software.

It can be very scary when you are experiencing this BSOD error 0xc000021a and your machine will not boot to the desktop, You worry you will lose all your data.  Well don't worry as this issue is easy to fix,  Just follow the steps listed below.  I have even created a video below which shows you how to Easily Fix The BSOD Error 0xc000021a On Windows 10.


How To Fix The 0xc000021a Error


Listed below are many methods that you can use to resolve the 0xc000021a error. Start with method 1 and work your way down the list until the issue is resolved.

Method 1 - Fix Corrupt Files

I always like to start by fixing corrupt files on your system as I have seen this resolve many non booting systems in my time.  I also like doing this first as it means we are not making any changes to the system.  To fix the corrupt files do the following.

-Insert your windows 10 DVD in to your system and boot to the DVD. (If your system does not have a DVD drive you can download a windows 10 ISO from the microsoft.com site and make a bootable USB flash drive)

On the first screen you get click on "troubleshoot".


Next click on "advanced options"



Then Click on "command prompt"



A black window should now pop up, in the window type chkdsk C: /f /r this will perform a chkdsk on your system which will /f = Fixes errors on disk, and /r locates and recovers bad sectors.  If you get a y/n prompt type y and hit enter.  Now reboot your machine and hopefully it will boot correctly now.




Method 2 - Startup Repair

If the previous method didn't work we need to perform a windows 10 startup repair.  Again boot to the windows 10 DVD. On the first screen you get click on troubleshoot.



Next click on "advanced options"



Then Click on "startup repair"



The startup repair program will start and will scan your windows 10 machine and fix any startup issues it finds.  When the repair has finished remove the windows 10 DVD from your system and reboot.

Method 3 - Disable driver signature enforcement

 Method 1 and 2 should fix 99% of 0xc000021a windows 10 startup issues, but if you are still having issues there are a few more things we can do. Boot to the windows 10 DVD.

On the first screen you get click on "troubleshoot"



Next click on "advanced options"



Next click on "startup settings"



Then click "disable driver signature enforcement" , then hit restart



Method 4 - Disable early-launch anti-malware protection

Repeat the steps in method 3 but at the last screen instead of selecting disable driver signature enforcement select Disable early-launch anti-malware protection, then hit restart your machine.

Method 5 - Uninstall recently installed software

Repeat the steps in method 3 but at the last screen instead of selecting disable driver signature enforcement select enable safe mode and select restart.  Hopefully your machine will boot to your windows 10 desktop.  If it does click on the start menu then type in programs and select "Programs and Features"



The below window will now popup.  Sort the programs by installed on,  Now uninstall as many recently installed applications as you can.  Now click on the "View installed updates" on the left hand side of the window.  This will show you the operating system updates which have been installed.  Again uninstall any recently installed updates.



When you are finished uninstalling recently installed applications / updates reboot your system.

Method 6 - Run a SFC Scan

Repeat the steps in method 5 and boot in to safe mode.  Now click on the start menu and type in cmd then right click on the program and select "Run as administrator" when the black window pops up type in sfc /scannow and hit enter. This command will scan all protected system files, and replace corrupted files with a cached copy that is located in a compressed folder at %WinDir%\System32\dllcache.  When the scan has finished reboot your machine.



Method 7 - Run a DISM Scan

Repeat the steps in method 6 but apart from running the sfc /scannow command from the cmd window type dism/online/cleanup-image/restorehealth and hit enter. This command will check installed windows updates / service packs for issues / corruption. When the scan has finished reboot your machine.

Conclusion Of 0xc000021a BSOD On Windows 10


Hopefully you have managed to fix this BSOD error 0xc000021a on your windows 10 machine. I created this post adding my personal experiences with this error and I also spent hours researching this error online finding many fixes which I have listed here.  I hope this article has been helpful for you,  I would be interested in your feedback in a comment below.  I would also be very grateful if you can share this article via the links below. 
How To Easily Fix The BSOD Error 0xc000021a On Windows 10 How To Easily Fix The BSOD Error 0xc000021a On Windows 10 Reviewed by Citrix Tips on 11:39 Rating: 5