How to Fix 0xC000021A Blue Screen Error in Windows 10/11

Hey there, Windows users! Dealing with the frustrating 0xC000021A blue screen error? Don't worry, we've got you covered. In this comprehensive guide, we'll walk you through the steps to resolve this pesky stop code error and get your system back up and running smoothly. Whether you're a tech-savvy enthusiast or a beginner, we'll provide easy-to-follow instructions to help you tackle this issue with confidence.

Step 1: Boot into Recovery Environment

When encountering the 0xC000021A blue screen error, the first step is to boot into the Recovery Environment (WinRE). This specialized environment allows us to access troubleshooting tools and advanced options to address system issues. To access WinRE, follow these steps:

1.1. Restart your computer and, when the Windows logo appears, hold down the power button to force a hard shutdown. Repeat this process two more times until you see the "Preparing Automatic Repair" message.

1.2. On the "Automatic Repair" screen, select "Advanced options" and then "Troubleshoot."

1.3. Choose "Advanced options" again and select "Startup Settings." Click "Restart."

1.4. Upon restart, press the appropriate key to enter Safe Mode or choose the "Enable Safe Mode" option using the function keys. Once in Safe Mode, navigate to the Troubleshoot > Advanced options > Command Prompt.

1.5. You have now successfully booted into the Recovery Environment and can proceed with the troubleshooting steps.

Step 2: Reverse Pending Actions

Now that we're in the Recovery Environment, it's time to address any pending actions that may be contributing to the 0xC000021A error. We'll use the DISM (Deployment Image Servicing and Management) command with the "/revertpendingactions" option to reverse any pending actions that could be causing system instability. Follow these steps to execute the command:

2.1. In the Command Prompt window, type the following command and press Enter:

DISM /image:C:\ /cleanup-image /revertpendingactions

2.2. Wait for the process to complete, and then restart your computer to see if the error has been resolved.

Step 3: Run System Scans

After addressing pending actions, it's crucial to run thorough system scans to detect and remove viruses, malware, or corrupted system files. We'll utilize two essential tools for this step: System File Checker (SFC) and Deployment Image Servicing and Management (DISM).

3.1. To run the System File Checker (SFC) scan, follow these steps:

- In the Command Prompt, type the following command and press Enter:

sfc /scannow

- Allow the scan to complete, and follow any on-screen instructions if prompted.

- Once the scan is finished, restart your computer.

3.2. To perform a DISM scan, use the following steps:

- In the Command Prompt, type the following command and press Enter:

DISM /Online /Cleanup-Image /RestoreHealth

- Let the scan run to completion, and then restart your computer.

Running these scans will help identify and repair any corrupted system files, ultimately addressing potential causes of the 0xC000021A error.

Step 4: Revert to a Previous State

If the previous steps have not resolved the issue, the next recourse is to utilize the System Restore utility to revert the system back to a previous working state. This feature allows you to roll back system settings and configurations to a point in time when your computer was functioning without errors.

4.1. To perform a System Restore, follow these steps:

- In the Command Prompt within the Recovery Environment, type the following command and press Enter:

rstrui.exe

- The System Restore window will open. Follow the on-screen instructions to select a restore point and initiate the restoration process.

System Restore can be a powerful tool in reverting problematic changes and resolving the 0xC000021A error.

Step 5: Check Hard Drive Health

As we continue troubleshooting, it's essential to assess the health of your hard drive using the Check Disk utility (CHKDSK). This tool can identify and repair disk-related issues that may be contributing to the blue screen error.

5.1. To run a CHKDSK scan, follow these steps:

- In the Command Prompt, type the following command and press Enter:

chkdsk /f /r C:

- You may be prompted to schedule the scan for the next system restart. Confirm the scheduling and restart your computer to allow the scan to run.

By checking the health of your hard drive, you can mitigate potential hardware-related factors contributing to the 0xC000021A error.

Step 6: Perform a Clean Installation of Windows

If all previous troubleshooting steps have not resolved the 0xC000021A error, a clean installation of Windows may be necessary. This method involves reinstalling Windows from scratch, effectively eliminating any software or driver conflicts, malware infections, or corrupted files that are impeding normal system boot-up.

6.1. Before proceeding with a clean installation, ensure that you have backed up all important data from your system to prevent data loss.

6.2. To perform a clean installation of Windows 10/11, follow these general steps:

- Create a bootable Windows installation media using a USB drive or DVD.

- Boot from the installation media and follow the on-screen instructions to initiate the installation process.

- During the installation, choose the option to perform a custom installation and format the existing system drive before proceeding with the installation.

Performing a clean installation of Windows should effectively resolve the 0xC000021A error by providing a fresh and stable system environment.

Congratulations! By following these comprehensive and friendly steps, you have gained the knowledge and tools to tackle the 0xC000021A blue screen error in Windows 10/11. Remember, troubleshooting system errors requires patience and attention to detail. While these steps provide extensive guidance, don't hesitate to seek professional assistance if needed. With determination and the right know-how, you can banish that pesky blue screen error and regain a smoothly functioning Windows system. Happy troubleshooting!