SOLVED – Error 0xc000021a in Windows 8 & 10

Windows Computer

Have you ever received this error message while using Windows 8 or 10?

0Xc000021A

I have, and it was not fun times. This error message means that your computer has run into a problem and needs to restart

A big blue screen appears, telling you it’s collecting some error information and will then restart your computer for you. In small print under that, it gives your error code, 0Xc000021A, and tells you that you can find out more information about the error online

Now before you get in a panic, let’s take a look at some ways to correctly fix this error, which usually happens after a Windows update.

Repair Windows Yourself

Since your Windows computer isn’t functioning normally, you’ll have to boot Windows manually.

  • To do that, hold down the “Shift” key on your keyboard while you select “Restart” from the power options for Windows. You may need to use a bootable Windows disc or bootable Windows USB drive if you can’t access the “Restart” function.
  1. A blue option screen should load that says, “Choose an option.” Select “Troubleshoot.”  Windows Troubleshoot
  2. In the Troubleshoot screen, select “Advanced Options.”                                                    advanced options
  3. Next, in Advanced Options, select “Startup Settings.”                                                          Start setting
  4. On the Startup Settings Screen,select “Disable driver signature enforcement” by pressing “F7” on your keyboard.Startup Settings
  5. Press “Enter” on your keyboard or the “Restart” button if one’s displayed.

Your computer will restart the way you’ve told it to. You can adjust your computer by using the different selections offered until you find the one that works for you.

Let Windows Repair Itself

Alternatively, you can choose the “Startup repair option,” where Windows automatically scans your computer to locate the problem.

  • Hold down the “Shift” key on your keyboard while you select “Restart” from the power options for Windows. You may need to use a bootable Windows disc or bootable Windows USB drive if you can’t access the “Restart” function.
  1. A blue option screen should load that says, “Choose an option.” Select “Troubleshoot.”  Windows Troubleshoot
  2. In the Troubleshoot screen, select “Advanced Options.”                                                    advanced options
  3. Next, select “Startup Repair,” which scans and tries repairing your computer automatically.  Startup Repair Win

Hopefully, Windows has found and repaired the problem that was causing your computer not to boot correctly.

Files That Cause Error “0Xc000021A”

The two files that are responsible for the “0Xc000021A” error are “winlogon.exe” and “csrss.exe.” The first file is in charge of logging in and out of Windows, as the name suggests. The second file is a Windows server or client file. If either of these two files gets damaged, the error occurs.

Windows can repair corrupted files and find missing files, but it can’t repair and fix hardware issues.

We hope this has helped you resolve your Windows logon error and you didn’t have to resort to doing a clean install of Windows 8 or 10.

Please let us know if this helped you, or you’ve figured out another successful way of resolving this error, other than what we’ve written. Thanks!

Posted by Heather on June 27, 2016

9 thoughts on “SOLVED – Error 0xc000021a in Windows 8 & 10”

Jason k

December 27, 2016 at 11:14 am

Windows 10 is just restarting in a continual loop-not allowing me to select a course of action to remedy this issue before restarting itself over and over, only to detect and notify you of the same issue. I’ve put the windows 10 disk in the drive before restarting however, it does not load the disk for me to select an alternative course of action, it just notifies you that your pic needs to restart over and over again. Further assistance would be appreciated.

Reply

JL

December 27, 2016 at 4:51 pm

I have this problem. Unable to fix it with any of the tips found googling. Repairing fails. Unable to re-install windows.

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Edward

January 5, 2017 at 12:53 pm

Same here as well. Neen trying to reinstall windows 10 pro back onto my samsumg laltop since monday night. It eomt get past the loading up for the first time. I contacted Microsoft and they said i jabe a corrupted harddrive. I followed the instructions to fix it with a dvd rom iso and again with a usb iso flash drive and still nothing. I always get the same blue screen with the same error code 0xc000021a what can be done or do i need to get a new harddrive? ?

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Eric

February 28, 2017 at 8:49 pm

I have 3 computer repair clients with the same exact issue. 2 of them are able boot into safe mode to use their PC but it will not boot normally. The hard drive in the third system completely died, so I replaced it with a brand new one and re-installed Windows 10. Now, only 1 week after that fresh installation with a brand new HDD, it shows this 0xc000021a error code and cannot even boot into safe mode. Hope someone can shed some helpful light on this frustrating issue!

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RrnR

March 5, 2017 at 3:12 pm

I have a Toshiba P50 laptop which has just started exhibiting this boot loop problem. It won’t boot from USB rescue media. I can boot to a DOS prompt window using the “Advanced” button, and that allowed me to inspect the C: drive, and run CHKDSK, which said it had repaired problems (and helpfully failed to save the log file), but it still won’t boot. The last time I shut it down it installed an update before turning off, so I suspect that update might be the culprit.

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Bill

March 5, 2017 at 5:36 pm

Same issue on my laptop! Auto repair does nothing. F7 does nothing but take me back to same loop. WTH is going on here?

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Rob Taylor

March 6, 2017 at 6:08 am

Just had this happen to me this morning. Initially got error L1C63X64.SYS and then stuck in the inescapable loop that other commenters describe above. Windows 10 won’t reset, can’t find any system restore points (there were loads) won’t safe boot, won’t self repair and won’t go back to the previous build.

The increasing recency of our posts suggests the latest Windows update has screwed something up enormously, or we’ve all fallen foul of the same super-smart malware.

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Jack G

March 6, 2017 at 9:14 pm

Same here. Blue Screen Of Death with 0xc000021a error after a Windows Update. None of the suggested fixes are working. Tried a home brew registry fix suggested on another site but some key instructions were left out and now I’m tapped out. Clean install is the next step I guess. Yay, Windows…

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Shweetha

March 24, 2017 at 1:17 pm

Hi.

I have been getting the same error code. I have a windows 8. I don’t have my disc either. My laptop asked to updated to windows 10, I tried to update it but it was not compatable. I have tried all of these options and non work. It’s a constant loop. I don’t know what to do anymore. Any advice that will be successful?

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