How to Fix Dell 0xC000021A Stop Code – 2 Ways + 1 Tip

Some Dell users have reported that they are experiencing problems with Dell 0xC000021A stop code after the update. What is causing this error problem? How do I fix it? Come to this article to find the answer!


By Yuka Updated on January 5, 2023

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User Case: HELP! Error Code 0xc000021a

“I'm currently using my laptop for a year and today when I opened my Dell Vostro 2420 I get this error message.”

Dell  0xC000021A

0xC000021A is a blue screen-of-death error that can occur on Windows 10, 8.1, 8, 7, Vista, and XP. Many users have reported encountering this stop code after upgrading Windows 10 to a newer version. It states that your computer has encountered a problem and needs to be restarted. The following provides you with the possible causes and solutions for this error message. Read on if you are interested.

Reasons Behind the Dell 0xC000021A Error

This problem occurs when updating Windows. So after the update it doesn't boot into windows and shows this blue screen of death and error. There are two files that are the main cause of this error. These files are listed below.

🎄 winlogon.exe. As the name of this file implies, this file is responsible for the logon and logoff operations within Windows. This file may be corrupted due to a mismatch in system files or third-party software. If this file gets corrupted, then this error will cause the computer to boot to Windows login.
🎄 csrss.exe. The second file that causes this error is Csrss.exe. This .exe file belongs to Microsoft server or client. Therefore, this file may also be corrupted, causing this error.

Possible Fixes for Dell Stop Code 0xC000021A

Any of the above components stop working properly and Windows stop code 0xc000021a may appear. Below you are provided with several possible solutions to help you fix this error message.

#1: Disable Driver Signature Enforcement

In order to fix this 0xC000021A Dell error message, you have to start Windows manually. In most cases, starting Windows in Safe Mode is not possible. Therefore, you have to start it using the "Force driver to have signature disabled" option in the "Advanced Boot Options". To access this option, follow the steps below.

  1. Restart your computer by holding down the Shift key in Windows and clicking Restart. If you cannot access the reboot option on your Windows, then you may need to boot via a Windows bootable USB.
  2. It will take you to an options screen. Select Troubleshoot to access the advanced tools.


  1. On the next screen, select Advanced Options.

Advanced Options

  1. On the next screen, you will see a large number of options. Select Startup Settings here.

Startup Settings

  1. Click the Restart button to reboot your computer into the Startup Settings screen. On the Startup screen, there will be a number of options for you to choose from. Press 7 or F7 marked to Disable driver signature enforcement.

Disable Driver Signature Enforcement

  1. Your computer will restart with the options you have chosen and now you can adjust your computer with different options.

>>> If it doesn't work, you can use the Command Prompt:

  1. Select the Command Prompt in Step 4 above.
  2. When the Command Prompt window opens. Type the following command and press Enter to run it.
  • bcdedit /set testsigning on

Set Testsigning On

  1. If it displays the message "The operation completed successfully", try booting your Dell computer. However, if it says Protected by Secure Boot policy, you must disable Secure Boot from the UEFI firmware.

>>> Disable Secure Boot from the UEFI firmware settings:

  1. In the Troubleshooting menu, go to Troubleshoot -> UEFI Firmware Settings.
  2. Click Restart.
  3. Once in the BIOS, select the Authentication section
  4. Set Secure Boot to Disabled.

Secure Boot

  1. Save the BIOS settings and exit. Now you can run the bcdedit /set testsigning on command from the Command Prompt.
  2. If you need to re-enable Driver Signature Enforcement, run Command Prompt again and use the bcdedit /set testsigning off command.

#2. Run SFC Scan

If the above methods do not solve your problem, you can use System File Checker to scan for problems related to corrupt files that cause Dell 0xC000021A Stop Code errors.

  1. Follow the steps above to get to the Startup Settings page. Press 6 or F6 to Enable Safe Mode with Command Prompt.
  2. After opening the Command Prompt window, enter the command mentioned below to run the SFC scan.
  • sfc /scannow

SFC Scan

  1. Make sure you do not abort the process and wait for it to complete. The results will be displayed when the scan is complete.

Bonus Tip: Back Up your Windows 10 PC Before Upgrading

Many users encounter various problems after releasing a new Windows update. The Windows 10 Dell 0xc000021a stop code in the article is just one of them. Some of the problems are well resolved, but some very serious issues can cause a black or blue screen on your computer.

To avoid encountering similar situations in future upgrades, it is recommended that you back up your Windows 10 computer before upgrading. This way, if you encounter similar system problems next time, you can quickly restore your computer to a normal state. AOMEI Backupper Standard is a free backup and recovery tool that you can use to create Windows 10 system backup and bootable media easily. It has very easy steps to follow, so even a computer novice can get started quickly. You can refer to the illustrated steps below to see how to use it.

Download FreewareWin 11/10/8.1/8/7/XP
Secure Download
  1. Open the free backup software and click Backup > System Backup.

System Backup

  1. It will automatically select the system partition and boot-related partitions. And you only need to choose a destination path to store your system backups.

Select Destination

  1. Click Start Backup to backup the Windows 10 system.

Start Backup

 ✨ Notes:
🎍 Options:
 You can write comments, compress or split an image file and enable email notifications.  
🎍 Schedule Backup: It supports you to run backup tasks automatically at fixed intervals, such as daily, weekly, monthly, event triggered and USB inserted. The last two are available in the Pro version.
🎍 Backup Scheme: It provides 3 backup methods (Full/Incremental/Differential). Differentiated backups are easier to restore, and you can upgrade to the Pro version or higher to enjoy it.  After upgrading, you can also enable the automatic backup cleanup feature to save disk space.

Final Words

Dell 0xC000021A error message is one of the typical errors encountered by Windows Update users. If you are being plagued by 0xC000021A on Windows 10, you can read this article carefully. The two methods provided in the article should help you fix this error.

After you have fixed the error, it is recommended that you back up your system with the best backup software mentioned in this article. Also use it to create a bootable media. The next time you encounter similar system problems, such as Windows Update 0x80080005, you can quickly restore your computer to a normal state with the help of this bootable media and system backup.

Yuka · Editor
Yuka, our dedicated editor at AOMEI Technology, is committed to bringing you valuable insights and guidance in data protection. Her mission is to empower everyone with her knowledge in computer backup and recovery, disk cloning, file synchronization, and more. Yuka's goal is to do her best to make complex tech tasks simple and ensure that your digital world remains safe and secure.