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Error 0xC000021A — Critical Process Died and BSOD Recovery

Criticalbsod

Overview

Fix Windows BSOD error 0xC000021A STATUS_SYSTEM_PROCESS_TERMINATED when a critical system process (csrss.exe or winlogon.exe) crashes during startup.

Key Details

  • Error 0xC000021A occurs when a critical Windows subsystem process terminates unexpectedly
  • The two critical processes are csrss.exe (Client/Server Runtime) and winlogon.exe (Windows Logon)
  • This error prevents Windows from booting and displays a blue screen on every startup attempt
  • Often caused by failed Windows Updates, incompatible drivers, or corrupted system files
  • Recovery must be performed from Windows Recovery Environment or installation media

Common Causes

  • Failed Windows Update leaving system files in an inconsistent state
  • Incompatible driver or software installed before the crash
  • Critical system files (csrss.exe, winlogon.exe, or their dependencies) corrupted
  • Registry hive corruption preventing critical processes from loading configuration

Steps

  1. 1Boot into WinRE: interrupt boot 3 times or use Windows installation USB > Repair your computer
  2. 2Try Startup Repair first: Troubleshoot > Advanced options > Startup Repair
  3. 3If repair fails, use System Restore: Troubleshoot > Advanced options > System Restore > pick a restore point before the error
  4. 4Run system file check from WinRE Command Prompt: 'sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows'
  5. 5Uninstall recent Windows Updates from WinRE: Troubleshoot > Advanced options > Uninstall Updates

Tags

bsod0xc000021acritical-processcsrssboot-failure

Related Items

windows-safe-mode-boot-issueswindows-recovery-environment-errors

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windows-000000EF-critical-process-diedWindows Error 0x000000EF — CRITICAL PROCESS DIED
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Frequently Asked Questions

Usually yes. Try in order: Startup Repair, System Restore, sfc /scannow from WinRE, and uninstalling recent updates. Full reinstall is a last resort — try 'Reset this PC > Keep my files' before clean install.