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0x00000139KERNEL_SECURITY_CHECK_FAILUREStop codeWidely reported

KERNEL_SECURITY_CHECK_FAILURE (0x139): 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

KERNEL_SECURITY_CHECK_FAILURE means Windows found that one of its critical internal data structures had been corrupted and stopped before the damage spread. Drivers are the usual cause, then memory and damaged system files. Update recently changed drivers and repair system files.

What it means

Windows checks its own critical data structures as it uses them. If one has been overwritten, for instance a list that no longer links up correctly, it stops immediately with bug check 0x139 rather than carry on with corrupted data.

The check is the messenger, not the cause. Something wrote over that data: most often a driver, sometimes faulty memory, occasionally damaged system files. Because the corruption may have happened well before it was detected, the file named on the blue screen isn't always the culprit.

After an upgrade

This stop code is common after a big Windows update or an upgrade from an older version, when old drivers meet a new kernel. Updating drivers usually clears it up.

Common causes

  • An outdated or incompatible driver, often after a Windows upgrade.
  • Faulty or unstable memory.
  • Corrupted Windows system files.
  • Third-party security or system utilities that hook into the kernel.

How to fix it

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

  1. Update drivers after an upgrade

    If the crashes began after a Windows update or upgrade.

    1. Open Settings > Windows Update > Advanced options > Optional updates and install the driver updates offered.
    2. Download current chipset, graphics, network and storage drivers from your PC or motherboard maker.
    3. Restart after installing.
    Did this fix it?

  2. 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?

  3. 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?

  4. Remove kernel-level utilities

    If you use third-party antivirus, system tuners or overclocking tools.

    1. Uninstall third-party antivirus, system optimisers and hardware tuning tools from Settings > Apps > Installed apps.
    2. Restart and use the PC for a day or two.
    3. Reinstall only the ones you need, in their latest versions.
    Did this fix it?

Is it just you?

25+ Microsoft Q&A threads discuss this, 1 active in the last 30 days. Most recent activity:

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

Sources

Frequently asked questions

Is KERNEL_SECURITY_CHECK_FAILURE a virus?

Almost never. It means Windows detected corrupted internal data, usually from a driver or memory.

Can RAM cause KERNEL_SECURITY_CHECK_FAILURE?

Yes. If memory tests show errors, fix those first.

Why did KERNEL_SECURITY_CHECK_FAILURE start after updating Windows?

Older drivers can misbehave after a big update. Updating drivers usually fixes it.

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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