What is Windows 10 error 0xc000021a

There has been a circle of people facing “Windows 10 error 0xc000021a”. This problem appears as a Blue Screen of Death with the following message “Your PC ran into a problem and needs to restart…”. After that Windows collects some info about the issue and reboots your computer trying to automatically solve the problem. You can also see the code of the issue at the very bottom of the screen. This problem means that your computer was crashed due to some system infraction. This may be caused by corrupted/missing files, driver issues, incorrectly installed updates or other unknown reasons. However, you should not be worried since we are going to help you rectify the problem in the article below.

bsod error 0xc000021a in windows 10

Automatic Repair

Download Windows Repair Utility

There are special repair utilities for Windows, that can solve problems related to registry corruption, file system malfunction, Windows drivers instability. We recommend you to use Advanced System Repair Pro to fix 0xc000021a error in Windows 10.

Download Windows Repair Tool

Manual Repair

Note that after several reboots due to the crash you will see ongoing messages Preparing automatic repair and Diagnosing your PC afterwards. When the diagnosis is finished you will see a new window popped up titled Automatic Repair and a message saying that your PC did not start correctly. Then click on the Advanced Options button. There will be a system repairing tab with all of the tools that are going to be used in this tutorial. And now let’s get to solutions themselves.

1. Disable driver signature enforcement

This is the first method that works if there were some update or driver-related problems occurred on your computer. Windows is imperfect and tend to encounter some hiccups while installing new updates or drivers (especially if you did it intentionally). Here is how to do this:

  1. On the first screen go to the Troubleshoot section.
  2. Then click on Advanced options.
  3. After that click Startup Settings.
  4. In the opened tab, hit Restart.
  5. The PC will restart and appear with the options list. You should press F7 and Enter to get back to your system.
  6. If the Windows bootup succeeds this time, then see if it requires installing updates or any software. If so, allow the system to do this.
  7. After that, reboot the computer as usual and then the computer should start without errors.
  8. In case your computer boots properly with disabled driver signature enforcement, but subsequent normal reboot does not work – try rolling back the drivers (if you were updating them before the problem occurred) or uninstall recently installed software and third-party programs, especially those that install virtual device drivers on the computer.

2. Fix corrupted files in Automatic Repair mode

If the previous method did not rectify the problem then try to fix corrupted files right after the crash. Some crucial files could be corrupted due to the interference of appendant programs or other intended system manipulations. Running advanced System File Checker (SFC) feature can define damaged or missing files that hinder Windows to boot up and immediately restore them. See how to do this:

  1. Firstly click on the Troubleshoot button.
  2. Then go to Advanced options.
  3. And click Command Prompt amongst other tools.
  4. As soon as the black window appears you should paste this command sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows and click Enter.
  5. When finished (the process takes some time), you will see the message that Windows found corrupted files and successfully repaired them.

3. Run System File Checker utility scan from the desktop

Basically, this method is also meant to fix damaged files, however, it only works if you do not experience difficulties with booting up Windows to the desktop. Do the following:

  1. Open Command Prompt by typing “cmd” into the searching box next to the Start menu.
  2. Then, type sfc /scannow command and click Enter.
  3. When the fixing process is done, restart your computer.

4. Run Startup Repair

If you do not want to touch command-related methods then you can make it easier by launching the repairing procedure right in the tab. It is meant to find files that were spoilt and rebuild them after detection.

  1. Click on the Troubleshoot button.
  2. Then go to Advanced options and click on the Startup Repair button.
  3. After doing so, Windows 10 will start scanning through the database of system files to see if something is missing/damaged and restore it afterward.

5. Scan Windows update/service packs for issues.

Running a DISM (Deployment Image Servicing and Management) scan can be effective if Windows conflicts with previously installed updates or services. Windows does not always deliver flawless updates. On the contrary, they can contain different bugs and snags that may disturb users’ experience with error 0xc000021a popping up, for example. This is how you can do this:

  1. Go to the searching tab next to the Start menu and type cmd.
  2. Then click on Command Prompt.
  3. After the console is opened, paste this command DISM /Online /Cleanup-Image /RestoreHealth and click enter.
  4. The DISM scan may last up to 20 minutes so be patient and do not cancel the process. Once finished, reboot your computer and see if anything has changed.


We have just found out that Windows 10 error 0xc000021a may be a sequence of corrupted files and other issues that occur on your computer. However, these are the most frequently used methods that have been fruitful in solving the problem recently. Some utilities are also capable of automatically finding and solving such issues. I would personally recommend using Advanced System Repair Pro. It can define the reason that causes the problem and feasibly fix the related errors.

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