How to Fix Windows Error Code 0xc000021a

It seems that plenty of Windows 8 and Windows 10 users are experiencing issues with the system startup. According to the reports, the PC ran into a problem and needs to restart. Whenever affected users are trying to restart their PC, the Windows Error Code 0xc000021a may appear mostly which is one of the BSOD (Blue Screen of Death) regarding issues. If you’re also facing the same error then you can follow this troubleshooting guide.

Blue Screens of Death (BSOD) can occur due to several possible reasons and can be fixed by performing some of the workarounds that are mentioned below. To be very precise, there can be system file issues, conflicts with the 3rd-party programs that are installed on the PC, Microsoft server or client-related issues, etc. So, without wasting any more time, let’s get into it.

How to Fix Windows Error Code 0xc000021a

If we talk about the actual error notice, affected Windows 8/10 users are getting “Your PC ran into a problem and needs to restart. We’re just collecting some error info, and then we’ll restart for you. (0% complete)”. If you’re also getting the same error notice, then you’re on the right page.

How to Fix Windows Error Code 0xc000021a

1. Unplug all peripheral devices

It may possible that you’ve connected multiple peripheral devices to the computer and somehow it’s causing issues with the system files or boot files. It’s recommended to unplug or disconnect all the peripheral devices and restart your computer to check whether the BSOD error is still occurring or not.

Make sure that you’re using the mouse, keyboard, and monitor to the PC except for other peripherals. Try booting the Windows OS from the USB drive or DVD to check for the problem.

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But if you’re unable to boot the system properly then make sure to remove every peripheral device except for the monitor to see if that helps or not.

2. Upgrade Windows OS via Media Creation Tool

The chances are also high that your Windows OS build becomes corrupted or some boot files are missing unexpectedly. That’s why you should upgrade your existing Windows OS via the Media Creation Tool with a USB drive. To do so:

  • Download the Media Creation Tool from the official Microsoft website.
  • Now, run the tool and click on Accept to the Applicable notices and license terms.
  • Click on Upgrade this PC now and the downloading process should start.
  • Once downloaded, the Media Creation Tool will start upgrading the system to the latest version.
  • Once done, restart the computer to check for the issue.

It’s also worth mentioning that some users have managed to fix the issue by installing an older version of the Windows OS build.

3. Create a Bootable USB Drive

If you try reinstalling Windows 10 OS on an alternative PC. In this way, you’ll be able to check if your bootable drive is actually booting in the first preference or not.

Note: The process is the same for both the DVD and USB drive.

  • Download the Media Creation Tool from the link above on the USB drive.
  • Connect the USB flash drive > Run the Media Creation Tool.
  • Click on Accept to the Applicable notices and license terms.
  • Choose to Create installation media (USB flash drive, DVD, or ISO file) for another PC.
  • Click on Next > Make sure to select the preferred language, architecture, and Windows edition.
  • Now, click on Next > Choose to USB flash drive.
  • Then click on Next > Wait until the installer completed the download process.
  • Finally, you’re ready to boot/reinstall the Windows to the problematic PC.
  • You can reinstall Windows 10 by following this guide.

4. Run SFC Scan

System File Checker (SFC) is a utility tool in Microsoft Windows that allows users to scan for corrupted Windows system files and restore them automatically. To do this:

  • Click on the Start Menu and type cmd.
  • Now, right-click on Command Prompt from the search result.
  • Select Run as administrator > If prompted, click on Yes to give admin privileges.
  • Once the command prompt window opens, type the following command and hit Enter to execute it:
SFC /scannow

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  • Wait for the process until it gets completed.
  • Once done, close the command prompt window, and restart your computer to check for the error again.

5. Run DISM Scan

Deployment Image Servicing and Management (DISM) is a command-line tool that is used to mount and service Windows images before deployment. To do so:

  • Click on the Start Menu and type cmd.
  • Now, right-click on Command Prompt from the search result.
  • Select Run as administrator > If prompted, click on Yes to give admin privileges.
  • Once the command prompt window opens, type the following command and hit Enter to execute it:
DISM /Online /Cleanup-Image /CheckHealth
  • Then type the following command and press Enter:
DISM /Online /Cleanup-Image /RestoreHealth

  • Now, wait for the process to complete and exit the command prompt.
  • Finally, restart your computer to check for the error again.

6. Reconnect the Hard Disk / SSD

Make sure to disconnect and reconnect the HDD/SSD on the computer to check whether the problem has been fixed or not. Just turn off the computer properly, remove the power cable from the socket and then open the lid to reconnect the installed Windows disk.

7. Check Your Hardware

Well, it may also be possible that somehow the connected hardware devices are conflicting some issues with the system boot files. In that scenario, once you open the lid of the computer (cabinet/laptop), make sure to remove the hardware devices such as RAM, HDD/SSD, CPU fan, GPU card, CMOS battery, etc.

Now, gently clean the ports or slots of the respective hardware items if there is any dirt/dust, moisture, etc. Once cleared, you can reconnect all the hardware items. Additionally, you should also check whether any of the RAM slots or RAM sticks are faulty or not. The same thing is also applicable for the CPU, GPU, cooling fans, etc.

You should also check whether any specific hardware component is overheating or not by touching them individually. It’s also important.

8. Rebuild BCD

Boot Configuration Data (BCD) is a firmware database for the boot-time configuration data on Windows. Microsoft’s new Windows Boot Manager uses BCD and replaces the boot.ini file. So, rebuilding the BCD on the Windows computer can fix the Windows Error Code 0xc000021a. To do that:

  • Insert a Windows 10 bootable media USB drive or DVD.
  • Then make sure to restart your PC.
  • Now, set the USB/DVD drive as a primary boot (first boot) device in the booting sequence by pressing the Boot menu (F10, F11, or F12).
  • Once the boot device is selected from the BIOS Settings menu, make sure to save changes.
  • Then restart the computer once again to check if the Windows 10 bootable drive is booting or not.
  • If booted, you should select the language, time/format, and keyboard input.
  • Now, click on the Next button > Select Repair your computer from the bottom left corner.
  • Open the Troubleshoot option > Select Advanced Options.
  • Open the Command Prompt window > If prompted, select your account and enter the password.
  • Now, execute the following command line one by one:
bootrec /FixMbr

bootrec /FixBoot

bootrec /ScanOs

bootrec /RebuildBcd
  • The repairing process of the Windows 10 installation files will begin and it will take some time.
  • have some patience and once the BCD rebuilding process completed, you can be able to reinstall the Windows OS on your PC to fix the BSOD issue.
  • Finally, the PC should reboot to the system normally.

9. Disable Driver Signature Enforcement

Disabling the Driver Signature Enforcement is a security measure that actually blocks drivers that aren’t digitally signed to run on Windows 10. To do so:

  • Click on the Start menu > Press and hold the Shift key + click on the Power button + select Restart.
  • Your PC should now boot into the Recovery menu.
  • Click on Troubleshoot > Click on Advanced options.
  • Select Startup Settings > Choose Restart.
  • Once the PC reboots, make sure to press the F7 key to select Disable driver signature enforcement from the list.
  • Finally, insert the Windows installation media drive and select Repair your computer.
  • You should select the Startup Repairing method.

10. Repair Corrupted Windows System Files

There are several tools available online that you can easily download and install on your Windows computer to repair corrupted Windows system files (if any).

11. Update BIOS

If you’re still having issues with the Windows Error Code 0xc000021a, then we’ll highly recommend you try updating your BIOS (Basic Input Output System) on the PC.

Note: If you aren’t an advanced user enough to perform this task then we’ll recommend you skipping this particular method. Updating the BIOS can be risky enough to brick your system if you’re not aware of the process. Do it at your own risk and responsibility.

However, most motherboard manufacturers are offering an automatic BIOS update system to the PC/Laptop so that the users can easily install the BIOS update (if available).

Otherwise, you can head over to the official website of the motherboard manufacturer and grab the latest version of the BIOS according to your specific model. You can also get the official user manual guide to perform tasks with the BIOS.

11. Replace Corrupted Registry Hive Files with Backups

The chances are high that Windows is trying to access the necessary registry hive files on the computer while booting it up. Obviously, the system is unable to load them because they’re corrupted or damaged somehow. So, replacing the corrupted registry hive files with backed-up data can come in handy. To do this:

  • Insert the Windows installation disc or USB drive into the problematic computer and restart it.
  • Once the computer starts booting up, head over to the BIOS settings and then select the disc/USB as the first preference for booting.
  • Now, save changes, and restart the computer again to boot into the Windows installation media. If prompted, press any key to boot from the installation media, press any key to do so.
  • Then select your preferred language, time zone, and keyboard input, etc.
  • Click on Next > Click on Install now > Click on Repair your computer.
  • Next, the Startup Options screen will appear.
  • Click on Troubleshoot > Select Advanced options.
  • Then click on Command Prompt > A Command Prompt window will open.
  • Now, type the following command in the command prompt window and press Enter.
c:
    • Head over to the specific partition or drive where the Windows OS is already installed. [such as C:/ or another drive if you’ve installed it anywhere else]
  • Type following command line and hit Enter to execute it:
cd windows\system32\config
  • Next, execute the following command line to display all the files and folders available in the directory:
dir
  • For each file only (not the folder) that’s present in the directory, execute the following command line individually: [Do the same command for every file]
ren (File Name) (File Name).old

For example; type ren SYSTEM SYSTEM.old for the SYSTEM file in the directory.

  • Once renamed each file in the directory, make sure to copy all of them and keep them separately as a backup file.
  • Now, execute the following command:
cd RegBack
  • Type and execute the following command line again to check whether all files and folders are available in the directory or not:
dir
  • Now, execute the following commands one by one:
copy /Y SOFTWARE

copy /Y SAM

copy /Y SYSTEM
  • Once all files/folders are renamed, you’ll need to put the registry hives back to the folders we’ve just renamed.
  • Then execute the command below and close the Command Prompt window as well as the Windows Recovery Environment:
EXIT
  • Finally, remove the Windows installation media disc/USB and restart the computer to check if that fixes the issue or not.

12. Reset BIOS on the PC

Plenty of users have mentioned that they’ve managed to resolve the Windows Error Code 0xc000021a by resetting the BIOS on their computer. It’s also quite useful in some scenarios and can be performed so easily if you’re using a desktop computer. To do this:

  • First, shut down the computer properly.
  • Now, disconnect the power cable from the computer or power socket. Make sure that there is no contact with the power source (electricity) to the computer.
  • Then remove the cabinet lid according to the model.
  • Locate the computer’s CMOS battery that has been placed on the motherboard. It looks like a circular coin/ring.
  • So, properly remove the CMOS battery out of the slot.
  • Clean the CMOS battery and the slot too.
  • Then wait for around 1-2 minutes > Now, make sure to put it back into the slot and check whether it fits perfectly or not.
  • Once done, close the cabinet lid > Connect all the power cables to the computer and power source.
  • Turn on the computer and check if that helps you or not. Your PC should successfully boot into the Windows system now.
  • Enjoy!

That’s it, guys. We hope you’ve found this guide useful. For additional queries, you can comment below.

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