Windows Stop Code 0xc000021a [Fixed by Experts]
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Written By Mansi Verma
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Approved By Tanushree Chatterjee
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Updated on 29 Mar, 2023 -
Min Reading 6 Min - Share
Summary: A new BSOD error with a bug check value 0xc000021a has captured our attention after users start posting queries about this error. In this blog, read why this blue screen error occurs and how to fix it without losing data.
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Several Windows users’ have posted queries on Reddit and Microsoft forum related to 0xc000021a stop code. Some said that this error code occurred after a Windows Update installation, while others stated that it appeared out of nowhere while working on their system. And, when they restarted their PC, it got stuck at a booting loop. Users posted their queries with different names for the error such as,
- Stop code 0xc000021a Reddit
- 0xc000021a loop
- Stop code 0xc000021a after update
- 0xc000021a windows 10 install
Refer to the following users’ queries from Reddit and Microsoft:
“My Windows 10 Pro PC stopped booting two days ago. It goes into the repair/diagnosing loop and has an error code 0xc000021a. I went through all the advanced options to repair it and to disable the blue screen. I am aware of some troubleshooting, which I have tried, but cannot fix. This error has got me worried. Could anyone tell how to fix it?”
Well, circumstances could be different, but the problem remains the same. So, how would you fix it?
Worry not! You can fix it by attempting the methods shared in this blog. However, before that, let’s first understand this error and its causes.
What is Stop Code 0xc000021a & how it occurs?
The stop code 0xc000021a represents the WINLOGON_FATAL_ERROR, which occurs when a user-mode subsystem, such as WinLogon or Client Server Run-Time Subsystem (CSRSS), is compromised. It additionally means that security can’t be guaranteed for your system due to this error. And in turn, the Windows Operating System (OS) switches to the kernel-mode, showing a blue screen.
Sometimes, when you restore your hard disk from a backup, the system files can be corrupted or faulty and may cause this error on your system. Other causes behind the 0xc000021a error may include a corrupted hard drive, faulty device drivers, incompatible software/app installed, and problematic Windows update.
Irrespective of the reasons, you can fix it. We’ve collated the best possible methods to help you get rid of such blue screen errors. You can attempt the below-discussed methods by following them step-by-step.
| Caution: Some of the given methods may cause data loss. Therefore, we suggest you take backup of your system data and then troubleshoot the problem. |
How to fix the 0xc000021a error code?
- Run SFC Tool
- Run Windows Defender Antivirus Tool
- Update/Uninstall Device Driver
- Uninstall Problematic Windows Update
- Run CHKDSK Command
- Uninstall Incompatible Software/Application
- Perform System Restore
Consider booting your PC into safe mode to prevent any element from causing trouble while you’re trying to fix a BSOD error.
To enter Safe Mode, follow the given steps:
- Restart your system; as soon as you see the Windows logo on the screen, reboot it again and repeat this step thrice.
- After that, you’d reach the Automatic Repair environment.
- There, click ‘Advanced options’, leading you to the ‘Choose an option’ screen.
- There, click Troubleshoot > Advanced options > Startup Settings > Restart.
- Once your system gets restarted, click F4 to enable Safe Boot.
Now that you’re booted into safe mode, you can proceed with performing troubleshooting methods.
Method 1: Run SFC Utility
- Press Windows + R to open the Run dialog box.
- Open Command Prompt and choose to run it as administrator.
- Then type the following command and press Enter.
DISM.exe /Online /Cleanup-image /Restorehealth
- Now, wait for a while as it may take some time to show system files that need to be fixed.
- Next, type SFC/scannow command and hit Enter.
- Let the process complete. Once done, close the window and try rebooting your system to check if the error is gone.
Method 2: Run Windows Defender Antivirus Tool
- Open System Settings and go to Update & Security > Windows Security > Virus & threat protection.
- The Windows built-in Windows Defender antivirus program will start scanning the PC for any viruses. If there’s a malware present on your system, it will show up in the results.
- Next, follow the instructions given on the screen to fix the windows stop code 0xc000021a. After completion, reboot your system and check if the problem is solved.
Method 3: Update/Uninstall Device Driver
- Press Windows + X, click Device Manager and then navigate to the device category where you want to update the drivers.
- Expand the device category and right-click on the driver. Choose Update driver.
- Next, choose to ‘Search automatically for updated driver software.’
- Let Windows look for the latest driver software available.
If you already have the latest driver, try uninstalling it and then re-installing it with the compatible one.
- Go to the device driver, which seems to be causing the issue, and right-click on it.
Choose Uninstall device.
- On the next prompt, click ‘Delete the driver software for this device’ and click Uninstall.
- Wait and let the process end. Now, close the window and check if the error is gone. Afterward, you can download the compatible device driver by visiting their manufacturer’s site.
Method 4: Uninstall Problematic Windows Update
- Go to System Settings > Update & security > Windows Update > View Update History.
- Next, click Uninstall updates and choose the update you recently installed, causing issues for your system. Finally, right-click on the update and click Uninstall.
- Click ‘Yes’ if the process asks for permission. Let the process end, and then reboot your PC.
Method 5: Run CHKDSK Command
| Caution: While performing the CHKSK command, you may end up losing data as it doesn’t read and store data from the bad sectors of the hard drive. We recommend you take backup of your system or recover your data with a powerful data recovery software. |
To run the CHKDSK command, follow the given steps:
- Run Command Prompt as administrator, type chkdsk /f /r D: in the open window, and press Enter.
- The command will scan and mark the bad sectors on the hard drive and fix the drive corruption.
- Once the process finishes, close the window, and restart your system.
Method 6: Uninstall Incompatible Software/Application
- Go to System Settings > Apps > Apps & features.
- Select the application which seems to be causing the error on your system, click on it, and select Uninstall.
- Wait until the process is completed. Once done, reboot the PC to see if the error persists.
Method 7: Perform System Restore
If the above methods don’t fix the stop code 0xc000021a, you can try performing System Restore. However, it brings the system to default or chosen restore point.
Therefore, backup your system data or in case of data loss, restore it using a reliable data recovery software, such as Stellar Data Recovery Professional. It is a DIY tool that lets you recover data from formatted, corrupted, unbootable, crashed, or BSOD-affected Windows systems and storage devices, such as HDDs, SSDs, USB drives, etc.
Once you’re done with backing up or recovering your data, proceed with the following steps:
- Type Create a restore point in the Windows search box.
- Next, under the System Protection tab, go to System Restore.
- Click Next > Next. Choose a restore point and click Scan for affected programs.
- It will scan for the programs and files that will be affected during the process.
- Wait until the process ends. Close the window and then reboot your PC.
Encountering a blue screen error with a stop code 0xc000021a error randomly, could be quite annoying. To tackle such BSOD errors, you can try out the DIY methods given in this blog, including running SFC utility, CHKDSK command, Windows Defender program, uninstalling a problematic Windows update or software, or performing System Restore. But be aware that methods such as running CHKDSK and System Restore may cause data loss. So, take a backup of your system data before performing these methods or restore it using reliable data recovery software.
If you’ve encountered any other BSOD error on your Windows PC, let us know in the comment section below!
Also Read: How to Fix the Error Code 0xc0000225?
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NO About The Author
Mansi is a seasoned tech enthusiast, holding over a decade of experience in writing blogs, articles, guides, press releases, and tips for different industries, including Data Recovery, IoT, Artificial Intelligence, and Robotics.
18 comments
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None of these steps work
Hello John,
Please provide a detailed explanation of the issue you are encountering.
I have this Blue Screen problem and would love to try any of the outlined solutions, but my computer won’t take any input. Cycles from – scanning and repairing drive (\\?\System Partition):100% complete- – to Blue Screen message ” device ran into problem we will scan and restart. Stop code error 0xc000021a.From there it goes to Support Assist and runs hardware scan, no hardware problem found
Hi Vernon,
Certainly, it appears that your computer is encountering a persistent boot loop, repeatedly cycling through the scanning and repairing drive process and subsequently displaying the 0xc000021a stop code, indicating a potential compromise in a crucial user-mode subsystem. This error can be caused by various factors, including corrupted system files, problematic Windows updates, or incompatible software. Despite the hardware scan not detecting any issues, it is essential to perform some basic troubleshooting. Firstly, attempt a power cycle by completely turning off the computer and restarting it after a brief interval. Additionally, ensure all hardware components are securely connected to rule out any loose connections that might be causing the problem. You can also try booting into Safe Mode by repeatedly restarting the computer during the boot process and enabling Safe Boot through the Advanced options in the Automatic Repair environment.
If these initial steps do not resolve the issue, it is advisable to explore more advanced troubleshooting methods as outlined in the blog post.However, it’s important to note that certain advanced procedures, such as running the CHKDSK command or performing a System Restore, may result in data loss. As such, it is highly recommended to back up your system data before attempting these methods. If you are unable to access your system or if the issue persists despite these efforts, seeking assistance from a professional technician.
Hello…
All your other options for repairing stopcode 0x000021a assume that the windows 11 windowsmanager has started. Not so in my case. Best I can do is the “safe mode” admin cmd, which refers to an “x” drive, which pretends
, and I cannot cd c:\ in order to do the other cmd options…
BTW…win 11 will somehow allow a fully normal logon screen, and after logon,
boots to the black screen, and, with the cursor being functional, can tweak some task manager settings, and the windowsmanager will run, FULLY OPERATIONAL; Until the next boot, WHERE I have to do it all over again…The so-called “X:\” drive will not “cd\c:\” making my cmd line worthless…
Please advise
Thank You.
Tom
1. Run an SFC scan (`sfc /scannow`) to check for and repair corrupted system files.
2. Perform a DISM command (`dism /online /cleanup-image /restorehealth`) to restore the health of your system image.
3. If those options don’t work, consider using Startup Repair from the Advanced Boot Options menu.
If these steps do not resolve the issue or if you’re unable to execute them in Safe Mode Command Prompt, it’s recommended to seek technical support from Microsoft or consult with a technician who can assist further based on your specific setup.
I had this error last night. after troubleshooting most of the day today and trying every command there is, from dism to chkdsk to all that and googling multiple things. Finally the thing that fixed it for me was:
when you go into recovery menu, (after failed startup). to go troubleshoot, advanced and then startup options, hit restart then you are presented a list of options (safe mode etc). I tried safemode and all the other options, and still blue screened. but i hit “disable driver verification” option and poof after a restart it magically worked and was able to load.
BUT when i logged in, windows gave me a message saying that it had uninstalled a recent windows update…so I’m not even sure what the driver thing did, other than maybe an update caused a driver to hang…but its fixed. I was beside myself, didnt want to uninstall/reinstall windows, and finding a flash drive and tossing windows on it is tedius to troubleshoot.
so even if you think it has nothing to do with drivers/driver verification, try that option! it worked for me at least.
Hi Raevyn,
We have outlined each method/steps for fixing problem related to 0xc000021a in detail. I’m happy to hear that your issue has been fixed.
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My pc Won’t enter safe mode, I have tried all 3 types (normal, networking, and with command prompt) and it just goes back to the BSOD. The password I remember setting for my account isn’t working so I can’t uninstall old updates or anything. Please help.
Hi Zandar,
You can try this below methods to enter your PC in safe mode:
When you can’t open Settings to get into safe mode, restart your device from the Windows sign-in screen. On the Windows sign-in screen, press and hold the Shift key while you select Power > Restart .
Hope this helps
I tried method 1 and it worked, thank you so much! This is the only thing I have tried that worked and you don’t understand how grateful I am for you help <3
You’re very welcome! I’m glad that it worked for you and resolved the issue. It’s always great to hear when a solution is successful, and I appreciate your kind words.
Method 1 worked for me. Thanks so much. I’ve been dealing with this for a week.
Thanks for the feedback Mike.
I followed method 1 and resolved.
Just correct the following:
DISM.exe /Online /Cleanup-Image /Restorehealth (Capital I in Image)
SFC /SCANNOW (Space after SFC, SCANNOW all capitals)
Thank you very much
I’m glad to hear that your issue was resolved using these methods. If you have any more questions or need further assistance, feel free to ask!
I followed method six described in the blog to fix Windows Stop Code 0xc000021a, and it works, I uninstalled some of the apps, and this error stopped popping. Thanks a lot for sharing the solution in detail.
I am glad it was helpful. Thanks for the feedback