Fix: WINLOGON FATAL ERROR 0xC000021A in Windows 10

How to Fix WINLOGON FATAL ERROR with Blue Screen of Death or BSOD having bug check value 0xC000021A in Windows 10.

Windows 10 is a stable version but the OS quite often shows Blue Screen errors with different stop codes. One such BSOD is WINLOGON FATAL ERROR that appears with a bug check value 0xC000021A. The issue turns the screen blue and shows the stop error, furthermore sometimes makes the computer restarting frequently. WINLOGON_FATAL _ERROR occurs due to corrupt or missing CSRSS  or Winlogon.exe and also mismatched system files. Here are some solutions that will certainly help you deal with the issue.


Here is how to fix WINLOGON FATAL ERROR 0xC000021A in Windows 10 –

1] Disable Signature Enforcement

WINLOGON FATAL ERROR occurs mainly because of corrupt CSRSS or winlogon.exe. When Window starts the system notices the file missing, corrupt or unable to read and goes into the blue screen error. Disabled signature enforcement let the system load without reading the culprit driver so the error gets fixed. However, this is not a permanent solution but once getting out of the BSOD you could follow further solutions.

  • Press Windows logo key and type cmd.exe.
  • After results appear, click on Run as administrator in the right flyout of the search preview. Or you can directly read this post to Open Command Prompt as Administrator in Windows 10.
  • Type bcdedit.exe /set nointegritychecks on and hit enter.
  • Restart your PC to experience successful login without getting  WINLOGON FATAL ERROR.
WINLOGON FATAL ERROR Blue screen of Death

2] Uninstall buggy Windows Update

To retain the OS in good condition, you need to install updates and patches once available. Microsoft has activated an automatic service for the Windows 10 system to facilitate users in this concern. But sometimes knowingly or unknowingly they push buggy updates that may cause WINLOGON FATAL ERROR. You can easily solve this trouble by uninstalling these files. The guidelines are as underneath –

  • Launch the Windows Settings app.
  • From the apparent app area, select Update & Security and load that its additional settings page.
  • On the subsequent screen, cross on to left pane and click on the View update history link.
  • Select the Uninstall updates link Located at the top.
  • The activity will load the Installed Updates immediately in a separate window.
  • On the current window, find out to the latest patch you have installed.
  • Perform a right-click on the same and choose the Uninstall option once it gets visible.
  • Pursue the on-screen guidelines until the eradication of update finally.
Uninstall button on cumulative update

3] Use Windows Security to remove malware

Nowadays, the internet becomes the most powerful tool in the world, yet the Security system is not strong enough to avoid malware. Users can be affected easily while visiting a website or making click on a suspicious link. Whenever invaders enter the system, they delete the necessary OS components. Some of the important DLL files go missing for them as well and that causes the result WINLOGON FATAL ERROR. We are glad to have Windows Security that is a great utility to remove these bugs easily. Let’s use this tool and remove them –

  • Press Win+S and let the Taskbar search appear on the screen.
  • Type Security and hit.
  • Once it opens, select option Virus & threat protection.
  • Jump ahead to the corresponding right pane and click on the Scan options link.
  • Choose the radio button against Full scan and then click Scan now to initiate the process.
  • Once the result shows any potential virus, select the Clean threats option.
  • Hit Remove and then the Start actions button to start removing them completely.

4] Run System File Checker to Resolve WINLOGON FATAL ERROR

Windows 10 with missing DLL files and corrupted resources is very much likely to suffer from WINLOGON FATAL ERROR. Fortunately, you are able to improve these components using a simple tool named System File Checker. SFC, in, short, will only be effective when it runs in an Elevated Command Prompt. Follow the beneath guidelines to complete the task –

  • Open the Windows Search.
  • Write cmd.exe in the stipulated typing space given here.
  • Once results prompt up, choose Run as administrator from the right of the preview.
  • Choose Yes to give confirmation once UAC / User account control dialog box appears locking the screen.
  • Type the following syntax and then press the Enter key –Sfc /scannow
  • Scanning and repairing thoroughly might be a time taking process, therefore, wait for the process to end.
  • Upon finishing, restart the device, check if WINLOGON_FATAL_ERROR occurs.

5] Repair Memory Problems

The problem in the Random Access Memory may also cause to provoke BSOD errors in the machine. This mainly happens when corruption is found in files that you have used recently. To avoid these cases, you need to fix these issues as soon as possible. For this problem, Microsoft provides a quite handy tool named as Windows Memory Diagnostic. Let’s proceed –

  • Invoke Taskbar Search using Win+S hotkeys.
  • Type Memory in the empty space and press the Enter key.
  • A small window will automatically prompt up on the display; click on “Restart now and check for problems (recommended)”.
  • The tool will restart Windows 10 as the first action.
  • In a few seconds, Windows complete the cycle of the rebooting process.
  • You will come across a blue color screen detecting memory issues on the startup screen.
  • When the progress touches 100%, Windows will reboot for the second time.
  • After completion, you will be able to check the result of the diagnosis in the Notification area of the System Tray.
windows memory diagnostic tool

6] Use Windows Blue Screen Troubleshooter

Stop errors are found to cause severe fatality to the device including damaging it fully. Considering this situation, the company launched Windows Blue Screen Troubleshooter which is a reliable resolution for this issue. Follow the below guidelines and apply the tool –

  • Open the Windows Settings app using Win+I hotkey.
  • From the appearing page, select Update & Security.
  • Click on the Troubleshoot option available on the left pane.
  • Go to the right and find out the Blue Screen option.
  • Click on the result and hit the Run the troubleshooter button.

7] Make space out of Disk Storage

For the execution of tasks on Windows 10, the device produces a good number of unnecessary files every day that usually keep on saving in the Disk space. Some times later they are stacked up as garbage in large quantities, they occupy huge space in the storage. Meanwhile, you notice the Disk Space running short and operational speed is affected. There is also a chance to have WINLOGON FATAL ERROR 0xC000021A. Windows 10 provides Disk Cleanup Utility that comes handy to wipe out the junk.

  • Hold Windows logo key down one the keyboard, type cleanmgr.exe, and then hit enter.
  • In a few moments, a wizard rolls out showing the files that require deletion
  • Click on the Clean up system files button.
  • in the next wizard, check all boxes available here except Downloads.
  • At last, hit the OK button.

8] Disable Automatic Reboot

When a device is affected with Error WINLOGON FATAL ERROR, Windows 10, in most cases, automatically restarts frequently. This will make the situation complicated as you cannot do an important task easily. Even while performing to resolve the issue, there is no enough room to deploy the workarounds. Therefore, considering this with the highest priority, we need to disable the activity immediately. Go with the steps below –

  • First of all, save and close if you are running any ongoing processes on your computer.
  • Open File Explorer using keys Win and E keys altogether.
  • Right-click on the This PC icon and select Properties option.
  • When the System window appears, select Advanced system settings from the left pane.
  • In System Properties window, you will be directly in the Advanced tab.
  • Click Settings located under the Startup and Recovery section.
  • In the System failure section, uncheck the box before the Automatically restart option.
  • Save these changes to the Windows by choosing the OK button.
WINLOGON FATAL ERROR Blue screen of Death

9] Update all the outdated Drivers

Device Drivers are essential for the OS and they also cause BSOD WINLOGON FATAL ERROR when becoming outdated. Updating the same is a necessary task to maintain the Operating System in good condition. However, all these drivers usually get updated automatically in Windows 10 whether they are built-in or from OEM partners. But when manual action is required device manager comes in the first place. Here is how to update –

  • Invoke the Windows search pressing Win+S hotkey.
  • Input devmgmt.msc in the text area and press Enter.
  • When Device Manager comes into view, have a close look for any items having Exclamation marks in the list on the console by expending and checking.
  • When found do a right-click on the driver and select Update driver option.
  • Repeat the same for all drivers.
  • Reboot Windows, check if there is any BSOD error in the system.

10] Install all available patches to fix WINLOGON FATAL ERROR 0xC000021A

According to Microsoft’s team, you should update the Windows 10 every time to grab with modern features. As to continue this process, Microsoft rolls out cumulative updates in a regular interval of time. Chances to gets affected increase with the outdated operating system that causes Error WINLOGON FATAL ERROR 0xC000021A. Therefore, you need to install the update patches when available. Follow the below instruction to do the task –

  • Open Windows Settings, the built-in app, by hitting Win+I hotkeys together.
  • In the app field, click Update & Security tile.
  • Windows Update page appears on the screen, switch to the right pane and click Check for updates button.
  • When all the patches start showing, hit the Download button to get the update files in the system.
  • Upon finishing the process, the installation will start automatically.
  • Reboot the Windows when asked in the end to finish the installation process.

11] Uninstall similar applications

Similar kind of programs in a system cause conflict often in between them in Windows 10. They end up making the system sluggish and ultimately Blues screen error. Here you need to restrict those programs from a collision that may lead to WINLOGON FATAL ERROR. The only way is to remove one of these by uninstalling. Here is how to proceed –

  • Hold down Win+X and select Apps and Features option from the top of the list.
  • You will be guided to the Apps Settings page.
  • In the list, move to the right pane and find programs with similar functionality.
  • Select them one by one and choose the Uninstall button located in the expanded pane.
  • Continue following the on-screen guidelines till the end when it disappears completely.
  • Restart Windows and once and after the sign-in screen is upfront enter credentials.

12] Use the DISM tool

Corrupted Windows image files are also responsible for causing WINLOGON FATAL ERROR 0xC000021A in Windows 10. However, when you need to fix these files instantly DISM tool is perfectly helpful. To run the command line utility, proceed with the following –

  • Open Run dialog box as stated in one of the previous methods.
  • In the available text box here, type cmd.
  • Press Ctrl+ Shift+ Enter shortcut keys to load Elevated Command Prompt directly.
  • Once it opens, type the following command tool –

DISM.exe /Online /Cleanup-image /Restorehealth

  • Press Enter key and let the DISM tool start working.
  • Now, all the faulty image files will be detected and fixed automatically.
  • It might be a long process, therefore, hold the patience until it finishes.
  • Lastly, restart the Windows to make this repairing effective.

13] Perform System restore

Receiving WINLOGON FATAL ERROR after such changes means there is something wrong with the Windows Registry. However, you have ability to prevent having a BSOD issue by performing System Restore. It’s a simple technique to head back to the previous point.

  • Open the Taskbar Search by making a press of Win+S hotkeys.
  • In the text field, type rstrui and hit Enter.
  • This will make the System Restore wizard appear on the screen.
  • Choose the Next button to proceed ahead.
  • When the next page comes in, click on Show more points option.
  • From the available list, click on the most recent date and time one and hit the Next button once again.
  • After the succeeding wizards loads, select Finish and let the utility start restoring.

14] Remove Third-party Anti-virus programs

Previously, users used to access third-party antivirus programs for removing the malware. But these days, Windows Security has become the prominent utility in this case. On the other hand, third-party anti-malware programs turned totally useless nowadays which causes occurring of WINLOGON FATAL ERROR. Therefore, the company recommends removing these programs to get rid of Stop errors. To complete the task, instructions are as following –

  • Press the Windows logo, type appwiz.cpl and then hit enter.
  • The actions will unroll the Programs and Features window.
  • Locate third-party antivirus applications in the appearing list.
  • Click on it, and then select the Uninstall option from the top ribbon.
  • Once Users Account Control prompts on the screen, hit Yes to proceed.
  • Follow further guidelines until the app gets fully uninstalled.

15 Settle down Hard Disk Bad sector

When you use the same Hard Disk for a long time, bad areas form in it that might trigger WINLOGON FATAL ERROR. You can easily fix this mess using the Disk Checking tool. Here, you have to enter into Elevated Command Prompt first to execute the utility. Later on, move with the below guidelines –

  • Go to keyboard, hold down Ctrl+Alt+Del keys at once.
  • On the tool UI, select the File option located at the upper left corner.
  • Choose Run a new task.
  • Once a dialog comes into view, enter “cmd” text in its typing box.
  • Input checkmark against the option “Create this task with administrative privileges”.
  • Now, hit Enter key to get access to Elevated Command Prompt straightaway.
  • On the subsequent page, type the following command, and then hit Enter –

chkdsk C: /f /r /x

  • Disk checking is a be a time taking process, hold it until finishes.
  • Restart the device in case the process gets over normally.
  • Once return back, check if there is any Blue screen error present.

16] Boot device in Safe Mode to fix WINLOGON FATAL ERROR

Windows 10  often gets affected of bugs and issues regardless of whatever the version is. During every critical problem, performing a Safe Boot comes out as a resolution. In this specific start-up, Windows loads limited applications that heal even major problems. Here, you need to walk with below guidelines to perform the task –

  • Begin with clicking on the Start Menu.
  • Select the Power icon
  • Choose Restart with a continuous press on Shift key.
  • Windows will reboot, you will come across an Advanced Blue screen showing few options.
  • Perform a click on the Troubleshoot option and load the next screen.
  • On this page, select Advanced Options and subsequently, click on “Startup Settings”.
  • Next, click on the Power icon and go with the Restart option.
  • Here, the Windows will reboot for the once more.
  • When the next Startup screen comes into view, you will notice a set of options including one to Enable Safe Mode.
  • From here, hit the F4 button at a stretch to enter into the Safe Mode.

We have discussed all the possible workarounds that can potentially solve WINLOGON FATAL ERROR 0xC000021A. These are proven solutions and should work for your case as well.

1] Disable Signature Enforcement
2] Uninstall buggy Windows Update
3] Use Windows Security to remove malware
4] Run System File Checker
5] Repair Memory Problems
6] Use Windows Blue Screen Troubleshooter
7] Make space out of Disk Storage
8] Disable Automatic Reboot
9] Update all the outdated Drivers
10] Install all available patches
11] Uninstall similar applications
12] Use the DISM tool
13] Perform System restore
14] Remove Third-party Anti-virus programs
15] Settle down Hard Disk Bad sector
16] Boot device in Safe Mode

That’s all!!

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Topics:  Windows
About Sunita
Love to play with Windows 11 and 10. Suggestion - Going for Registry change or system files edit then remember to take a backup or create a restore point before Starting.