How to Fix BSOD 0xc000021a (Status System Process Terminated)

By ErrorFix · Updated October 13, 2026 · 8 min read

What error 0xc000021a means

The status code 0xc000021a means STATUS_SYSTEM_PROCESS_TERMINATED. Windows relies on a handful of critical user-mode processes — most famously csrss.exe (the Client Server Runtime Subsystem) and winlogon.exe (which handles logon). If one of these processes terminates unexpectedly, Windows has no safe way to continue, so it deliberately crashes with this blue screen rather than running in a half-broken state.

In the real world, this blue screen shows up most often right after a Windows update or a driver installation. The update replaces a system file or driver with a version that doesn't match what the critical processes expect, and the process dies on the next boot. Less commonly, malware damage or an interrupted update leaves the system in a mismatched state. The good news: because the trigger is usually one identifiable recent change, undoing that change fixes it.

Common causes

• Faulty Windows update: an update ships a mismatched or corrupted core system file — the most common trigger.
• Incompatible or corrupt device driver: a bad driver can take down a critical process during startup.
• Corrupted system files: damaged csrss.exe, winlogon.exe, or their dependencies.
• Malware damage: infections that patch or replace system files can kill critical processes.
• Interrupted update: a power cut or forced shutdown mid-update leaves files in a mismatched state.

How to fix error 0xc000021a — step by step

Work through these fixes in order. Start with step 1 if Windows won't boot normally.

1. Boot into the Windows recovery environment. If Windows blue-screens during startup, interrupt the boot three times in a row by holding the power button when the Windows logo appears — on the third attempt Windows opens the recovery environment automatically. Alternatively, boot from a Windows installation USB, choose your language, and click "Repair your computer."
2. Boot into Safe Mode. In the recovery environment, go to Troubleshoot, then Advanced options, then Startup Settings, then Restart. When the menu appears, press 4 for Safe Mode. Safe Mode loads only essential drivers and services, which is often enough to get past the crashing process so you can undo the offending change.
3. Uninstall the most recent Windows updates. In Safe Mode, open Settings, go to Windows Update, then Update history, then Uninstall updates. Remove the most recently installed update — especially any update installed just before the blue screens began. Restart and see if Windows boots normally.
4. Uninstall or roll back recently added drivers. Right-click Start and open Device Manager. Look for any device whose driver was installed or updated just before the crashes. Right-click it and choose "Uninstall device" (checking "Attempt to remove the driver" if offered), or open Properties, go to the Driver tab, and choose "Roll Back Driver." Pay special attention to display and storage drivers.
5. Run SFC and DISM offline from recovery. If Safe Mode won't boot either, open Command Prompt from the recovery environment (Troubleshoot, then Advanced options, then Command Prompt). Run sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows, adjusting the drive letter to match your Windows drive — letters shift in recovery, so verify with diskpart then list vol first. Then run DISM /Image:C:\ /Cleanup-Image /RestoreHealth with the matching drive letter.
6. Use System Restore to roll back. In the recovery environment, go to Troubleshoot, then Advanced options, then System Restore. Choose a restore point dated before the blue screens started and let it complete. System Restore reverts system files, drivers, and registry settings without touching your personal files.

Did this fix it? Quick checklist

• Windows boots past the login screen without the blue screen
• The problematic update or driver is identified and removed
• No 0xc000021a crash after updates reinstall
• A fresh System Restore point is created for safety

If the system is stable again, create a new restore point right away (search "Create a restore point" in Start) so you have a known-good fallback. If crashes return after Windows reinstalls the same update, use the "Show or hide updates" troubleshooter from Microsoft to block that specific update until a fixed version ships.