- Download the Media Creation Tool.
- Run Media Creation Tool and accept the License Terms.
- Choose Create installation media (USB flash drive, DVD, or ISO file) for another PC.
- Select the preferred language, architecture, and edition.
- Click Next.
- Select ISO file.
- Save the ISO file to a preferred location and wait until the download completes.
- Insert DVD and use any third-party burning tool to create the bootable Windows 10 DVD.
2. Run a BSoD fixer
As mentioned before, the cause of this stop error is hard to pinpoint. To gain more time and fix the BSoD quicker, we recommend running a general blue screen troubleshooting tool.
Restoro is powered by an online database that features the latest functional system files for Windows 10 PCs, allowing you to easily replace any elements that can cause a BSoD error.
This software can also help you by creating a restore point before starting the repairs, enabling you to easily restore the previous version of your system if something goes wrong.
This is how you can fix registry errors using Restoro:
- Download and install Restoro.
- Launch the application.
- Wait for the software to identify stability issues and possible corrupted files.
- Press Start Repair.
- Restart your PC for all the changes to take effect.
As soon as the fixing process is completed, your PC should work without problems, and you will not have to worry about BSoD errors or slow response times ever again.
Disclaimer: This program needs to be upgraded from the free version in order to perform some specific actions.
3. Unplug all peripheral devices
Another possible culprit that can certainly cause critical system errors involves peripheral devices. Peripheral devices can occasionally cause a stall in the loading process.
Furthermore, that halt can lead to more than a few errors, including the Blue Screen of Death crash with the 0xc000021a error code that comes along.
So, make sure to leave only the mouse, keyboard and monitor plugged in while booting from USB or DVD.
You should disable everything else just in case one of the secondary devices are preventing the Windows 10 installation process to commence.
On the other hand, if you’re still unable to boot, make sure to check the additional steps.
4. Upgrade via the OS
- Download the Media Creation Tool.
- Run Media Creation Tool and accept the Licence Terms.
- Choose Upgrade this PC and the downloading process should commence.
- Once it downloads files, Media Creation will start upgrading.
Some users managed to resolve the issue by installing an older Windows iteration and then upgrading to Windows 10 with the Media Creation Tool.
5. Run SFC
- Right-click the Start menu and run Command Prompt (Admin).
- In the command line type the following command and press Enter:
- Wait for the scanning procedure to end and look for improvements.
Sometimes, the corruption of system files can lead to a world of problems in many departments, including Windows 10 reinstallation.
Due to virus infection or integrity issues, certain boot files can get corrupted which will, eventually, result in a critical system error. Just like the installation error that bears the 0xc000021a code.
There are various ways to address this, but the best way to overcome this and similar issues is to use System File Checker and scan for errors.
In addition, it’s highly recommended to perform a full scan with a third-party antivirus in order to get rid of the malware infections.
If this wasn’t enough, make sure to continue with the additional solutions we presented below.
6. Try running DISM scan
- Start Command Prompt as an administrator.
- Type the following command and press Enter:
DISM /Online /Cleanup-Image /RestoreHealth
- The DISM scan will now start. The scan can take about 20 minutes or more, so be patient.
Once the scan is finished, check if the problem is still there. If you were unable to run SFC scan before, try running it after completing the DISM scan.
7. Rebuild BCD
- Insert the Windows 10 bootable media (USB stick or DVD) and restart your PC.
- Set USB/DVD as primary boot device. Either by entering the Boot menu (F10, F11, or F12) or from the BIOS settings.
- The loading process of the installation file should commence.
- Select the language, time/format, and keyboard input of choice and click the Next button.
- Select Repair your computer from the bottom left corner.
- Open the Troubleshoot option.
- Select Advanced Options.
- Open Command Prompt. Select your account and enter the password if asked.
- In the command line, type the following commands and press Enter after each:
- This should finalize the repair procedure and you should be able to start Windows 10 installation setup just as intended.
In the preferred scenario, after you rebuild BCD, the installation files should load seamlessly so you can finally move to the reinstallation process.
8. Disable Driver Signature Enforcement
- Open Start.
- Press and hold Shift, click on the Power button, and select Restart.
- Your PC should boot in the Recovery options menu.
- Select Troubleshoot.
- Choose Advanced options.
- Select Startup settings.
- Choose Restart.
- One the PC restarts, press F7 to select Disable driver signature enforcement.
- Insert the installation media and look for changes.
Disabling of Driver Signature Enforcement is a security measure that blocks drivers that aren’t digitally signed to run in Windows 10.
9. Check the HDD health
- Open This PC or File Explorer.
- Right-click on the system partition and open Properties.
- Select the Tools tab.
- Click on the Error checker tool and wait for the procedure to finish scanning.
However, if you’re more into details, maybe you can use one of 14 HDD diagnostics and monitoring tools we enlisted in this article. We highly recommend checking it out.
We certainly hope that this was a helpful read and that you’ll be able to overcome the installation error with the stop code 0xc000021a in Windows 10.
Additionally, make sure to share your questions or suggestions regarding this and similar installation errors in the comments section below.
This post was written by Aleksandar Ognjanovic and was first posted to WindowsReport