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0x000000EFCRITICAL_PROCESS_DIEDStop codeWidely reported

CRITICAL_PROCESS_DIED (0xEF): what it means and how to fix it

By Gaurav Rawat · Updated Oct 2, 2026 · Checked against Microsoft documentation · How this page is made

Quick answer

CRITICAL_PROCESS_DIED means a Windows process that must always be running stopped unexpectedly, so Windows shut down to protect itself. Corrupted system files, a failing drive and faulty drivers are the usual causes. Repair system files and check the drive first.

What it means

A handful of Windows processes are marked critical: if one of them stops, Windows can't keep running safely. When that happens it stops the PC with bug check 0xEF.

The process didn't just close. Something made it crash or be terminated. On home PCs that's most often damaged system files (after a failed update or a forced shutdown), a drive that's returning bad data, or a driver corrupting memory.

If Windows won't start at all

If you hit this blue screen on every boot, Windows usually opens the recovery environment after a couple of failed starts. From there you can run Startup Repair, System Restore or uninstall the latest update without getting into Windows.

Common causes

  • Corrupted Windows system files after a failed update or power loss.
  • A failing SSD or hard drive.
  • A faulty or incompatible driver.
  • Malware or security software interfering with system processes.
  • Faulty memory.

How to fix it

Safest and most likely fixes first. Readers' answers to "Did this fix it?" reorder this list over time.

  1. Repair Windows system files

    If the crashes started after an update, a power cut or a forced shutdown.

    1. Right-click Start and open Terminal (Admin).
    2. Run DISM /Online /Cleanup-Image /RestoreHealth and wait for it to finish.
    3. Then run sfc /scannow.
    4. Restart once both have completed.
    Did this fix it?

  2. Check your drive's health

    If the PC is slow, freezes, or the crashes happen during file activity.

    1. Open Terminal (Admin) and run chkdsk C: /scan.
    2. If it reports problems, run chkdsk C: /f and restart when asked.
    3. Install your drive maker's tool and check its health or SMART status. Back up immediately if it reports warnings.
    Did this fix it?

  3. Remove the update that started it

    If the blue screens began right after a Windows or driver update.

    1. Open Settings > Windows Update > Update history and note what installed the day the crashes started.
    2. For a Windows update, scroll to Related settings > Uninstall updates and uninstall it.
    3. For a driver, open Device Manager, right-click the device, choose Properties > Driver > Roll Back Driver.
    4. Restart and see whether the crashes stop.
    Did this fix it?

  4. Use System Restore or Startup Repair

    If you can't get into Windows, or the other fixes didn't help.

    1. Open Settings > System > Recovery > Advanced startup > Restart now. If Windows won't load, it opens recovery after a couple of failed boots.
    2. Choose Troubleshoot > Advanced options.
    3. Try Startup Repair first, then System Restore to a point from before the crashes began.
    Did this fix it?

  5. Test your RAM

    If the crashes are random, or this stop code alternates with other memory-related ones.

    1. Save your work, press Win + R, type mdsched.exe and press Enter.
    2. Choose Restart now and check for problems, and let the test run to the end.
    3. When Windows starts, check the result notification, or Event Viewer > Windows Logs > System, filtered for MemoryDiagnostics-Results.
    4. Any errors mean a memory problem. Reseat the sticks, test them one at a time, and replace any that fail.
    Did this fix it?

Is it just you?

25+ Microsoft Q&A threads discuss this. Most recent activity:

Checked Oct 2, 2026. Refreshed automatically every few days.

Sources

Frequently asked questions

Will CRITICAL_PROCESS_DIED delete my files?

No, but repeated crashes and a failing drive can. Back up as soon as you can get into Windows.

How do I fix CRITICAL_PROCESS_DIED if Windows won't start?

Let Windows open the recovery environment after failed boots, then use Startup Repair, System Restore or Uninstall Updates under Troubleshoot > Advanced options.

Can a bad SSD cause CRITICAL_PROCESS_DIED?

Yes. If system files are read back corrupted from a failing drive, critical processes can crash.

Written by

Gaurav Rawat

Gaurav Rawat is a full-stack developer from Jaipur with a B.Tech in Information Technology. At PC Decoder, he writes practical guides on Windows 11 updates, error codes, and fixes for apps that stop working after an update, with an emphasis on clear steps that actually solve the problem.

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