Windows 10 cannot boot, 0xc000021a error

2 days ago I turned on my laptop. It tried to load when the Window logo comes up, then an error occurred: code 0xc000021a.

The laptop keeps restarting and won't show the box to get into repair mode. I tried turning the computer off and restarting, still it can't get to repair mode.

I had windows 7 and upgraded to Windows 10. Now my F2 and F12 don't work.

What can I do?

This issue arises when Windows is updated. So, after the update, it doesn’t boot to Windows and displays this blue screen of death along with error. There are two files that are the major cause of this error to appear. These files are listed below:-

winlogon.exe: As the name of the file represents, this file is responsible for the login and logout operations inside Windows. This file can be damaged due to mismatch of System Files or 3rd party softwares. If this file gets damaged, then this error causes the PC to boot to the Windows Login.

csrss.exe: The second file causing this error is Csrss.exe. This .exe file belongs to Microsoft server or client. So, this file can also be damaged resulting this error.

Solution For this type of issue :

Booting Windows Manually:

In order to resolve this problem, you have to boot Windows manually. Booting the Windows in safe mode won't work in most cases. So, you have to boot it using force drivers to have signature disabled option available inside Advanced Boot Options. To access this option, follow the steps below.

1) Restart the PC from Windows holding the Shift key and clicking on the Restart. If you can’t access the Restart option on your Windows, then you might need to boot through a Windows bootable USB.

2) It will take you to an option screen. Select Troubleshoot to access the advance tools.

3) From the next screen, choose the Advanced option.

4) On the next screen, you will see a plenty of options. All you need to do is to click on Startup Settings as shown in the picture below.

5) On the startup screen, there would be a number of options to select from. Press F7 labelled as Disable driver signature enforcement.

Your PC would restart with the option you selected and now, you can tweak your PC using different options.

If this solution doesn't helps you then you can use System File Checker Scan in order to resolve issues related to corrupted files causing this error.