How To Fix Windows 10 Boot Error Bsod 21a

How To Fix Windows 10 Boot Error Bsod 21a

The bsod 21a error usually occurs when the Winlogon.exe or Csrss.exe files either stop working or are corrupt. This is caused due to corrupt files on the computer, incomplete installation of some software or when a system update is interrupted and stopped before it is completed.

The first thing you should try is to boot into your system in safe mode with networking. This will not only allow you access to the computer but also provide network access to diagnose and solve the problem you are facing. If you are unable to boot in safe mode with networking, use your Windows installation media and select the option of repair my computer. I must inform you that doing so will lead to the loss of all your files and data.

How To Fix Windows 10 Boot Error Bsod 21a

You may receive error code “0xc000021a” on Windows 10 which causes a blue screen error or BSOD. This error is normally caused by one of these two files:

• winlogon.exe
• csrss.exe

The “winlogon.exe” program or service manages the logon and log off process on Microsoft Windows 10. The “csrss.exe” file is a core operating system file that handles the graphical instruction in the operating system. If you receive this error, it is possible that one of these files is corrupt, deleted, or has been replaced by 3rd party software.

To fix the problem, insert your Windows 10 installation DVD on your optical drive then restart the computer and boot with your DVD. Go to “Troubleshoot,” “Advanced options” then select “Command Prompt.” In the command prompt, type the following command then hit Enter:

chkdsk c: /f /r

If this doesn’t work, repeat the same steps to go to “Advanced options” then select “Startup Repair.” This will scan your computer and fixes any startup-related issue. When repair is finished, remove the Windows 10 installation DVD then restart the computer.