How to fix error 0xc000021a in Windows 11

Solution Steps

1. 1 Boot into Safe Mode: Restart your PC and press F8 (or Shift + F8) before Windows loads. If Safe Mode works, you can try to uninstall recently installed software or drivers. Press Windows key + X, select 'Device Manager', and check for devices with yellow exclamation marks. Right-click and choose 'Uninstall device'. Also, go to Settings > Apps and uninstall any recently installed programs.
2. 2 If Safe Mode doesn't work, use Windows Recovery Environment (WinRE) to run Startup Repair. Boot from installation media, click 'Repair your computer', then 'Troubleshoot' > 'Advanced options' > 'Startup Repair'. This can fix corrupted system files that cause Winlogon to fail.
3. 3 Open Command Prompt from WinRE and run 'sfc /scannow' and 'DISM /Online /Cleanup-Image /RestoreHealth' to repair system files. These commands replace corrupted files with healthy ones.
4. 4 Check for malware: From WinRE Command Prompt, run 'cd C:\Windows\System32' and then 'ren winlogon.exe winlogon.exe.old' to temporarily rename the file. Then copy a backup from the Windows installation media: 'copy D:\Windows\System32\winlogon.exe C:\Windows\System32\winlogon.exe' (replace D: with your installation media drive). This replaces the corrupted file.
5. 5 If the issue persists, perform a system restore: From WinRE, go to 'Troubleshoot' > 'Advanced options' > 'System Restore' and choose a restore point before the error started.
6. 6 As a last resort, reset Windows: 'Troubleshoot' > 'Reset this PC' and choose 'Keep my files' or 'Remove everything'.