How to Troubleshoot Error Code 0xc000021a on Windows PC

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Since the launch of Microsoft Windows 10, there have been many problems. A few years later, when Microsoft started releasing updates, some bugs have been fixed, but many other problems are still present. Error code 0xc000021a is one of them. Users are still facing the problem of error code 0xc000021a on their Windows computers and laptops.

While working on your computer, you suddenly see the error code 0xc000021a. This error indicates that there is a problem in the computer and it needs to be restarted. This problem manifests itself in a very blue screen of death. This problem persists even after restarting the computer. You need to restart your computer to fix this error, but after some time you will see this error again. Therefore, you need to fix this error permanently.

This problem occurs when you install new Windows updates. After installing a Windows update, it does not show up in Windows and shows a blue screen of death with an error.

What causes the error 0xc000021a?

The 0xc000021A error usually occurs when the Winlogon.exe or Csrss.exe files are damaged.

Winlogon.exe is responsible for handling login and logout processes.
Csrss.exe belongs to Microsoft’s client or server ‘Runtime Server Subsystem’.

The above-mentioned files may be corrupted due to :

  • Incorrect device drivers installed
  • Some files are missing from third-party software.
  • The system files have not been properly allocated.

How to resolve the error 0xc000021a?

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Perform an SFC scan

  1. Press Windows+R
  2. Type cmd and run it as administrator.
  3. Enter the sfc/scannow command to restore corrupted system files > press Enter.

Canceling Windows updates

  1. Insert the Windows 8/8.1 installation DVD/USB disk or recovery disk.
  2. Restart your computer or laptop Click Next
  3. Then click on the Restore Computer link.
  4. Click Troubleshooting > Advanced > Command Prompt
  5. At the command prompt, type dism.exe /image:C:/cleanup-image /revertingactions (C is your computer’s system drive).
  6. Then press Enter to run the command and cancel the upgrade.

Updating the Windows operating system

  1. Insert your Windows 8/8.1/10 installation DVD/USB disk or recovery disk.
  2. Click Next after the installation screen appears.
  3. Click Repair Computer.
  4. Click on Repair Computer under Advanced Startup Features,
  5. Click Troubleshooting.
  6. And click Refresh Computer.
  7. After updating your Windows operating system, the error will no longer appear.

Resetting Windows

  1. Insert your Windows 8/8.1/10 installation DVD/USB or restore disk.
  2. Click the Next button after the installation screen appears.
  3. Click the Computer Repair button.
  4. Click Troubleshooting in the advanced startup options.
  5. Click on the Reset PC button.

Reboot in safe mode

  1. Click Advanced Options > Boot Options.
  2. On the Startup Options screen, click Restart.
  3. Turning on safe mode when running over the network

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Frequently Asked Questions

  1. You need to restart your computer by holding down the SHIFT key on your keyboard to open additional startup options.
  2. Then on the computer screen, select Troubleshooting.
  3. On the Troubleshooting -> Reset this PC page
  4. Go to Reset this PC -> Save My Files.

The BSoD is usually caused by improperly installed software, hardware, or settings, which means it's usually fixable.

While starting up, hold down the F8 key until the Windows logo appears. A menu will appear. Then release the F8 key. Use the arrow keys to highlight Safe Mode (or Safe Mode with networks if you need to use the Internet to fix the problem), then press Enter.

Error 0xC000021A is a Blue Screen of Death or BSoD error (see the Blue Screen of Death guide) that occurs when the Windows subsystem is affected in user mode.