What Causes Kernel Security Check Failure?

Kernel Security Check Failure (stop code 0x00000139) is a Windows blue screen that appears when the system runs an internal safety check and finds that important data or memory has been corrupted. The most common causes are outdated or incompatible drivers, faulty RAM, corrupt system files, disk errors, or malware. Windows stops rather than risk running with damaged data.

Why this happens

Windows constantly verifies the integrity of data structures in memory. If one of these checks finds that something has been changed in a way that should be impossible, it means corruption occurred, and Windows halts to prevent damage.

• Outdated, buggy, or incompatible device drivers, often after upgrading Windows.
• Faulty or unstable RAM, including overclocked or mismatched memory.
• Corrupt Windows system files from a bad update or unclean shutdown.
• Bad sectors or errors on the system drive.
• Malware that tampers with system memory or files.

Is this normal?

No. It signals real corruption somewhere in drivers, memory, files, or the disk. A single event may be a fluke, but if it repeats there is a definite problem that needs to be found and fixed.

Does it cause any problems?

Yes. It crashes the system and loses unsaved work, and repeated crashes can interrupt your use of the PC. If the cause is failing memory or a failing drive, ignoring it can lead to data loss over time.

How to fix or check it

1. Restart and note whether it happens again and what you were doing when it did.
2. If it loops, boot into Safe Mode from the Recovery Environment so you can work without the crash returning.
3. Update your drivers from the manufacturer sites, especially display, storage, and chipset drivers. Roll back any driver you updated just before the crashes began.
4. Run the Windows Memory Diagnostic (type mdsched.exe and restart) to test your RAM, and try one stick at a time if you have more than one.
5. Open Command Prompt as administrator and run sfc /scannow, then DISM /Online /Cleanup-Image /RestoreHealth.
6. Run chkdsk /f /r C: to check the disk for errors.
7. Scan for malware with Windows Security or another trusted scanner.
8. If it started after a Windows update, uninstall that update or use System Restore to return to a stable point.

Frequently asked questions

Is this error caused by bad RAM?

Faulty RAM is one of the most common causes, so run the memory test early. But drivers, corrupt files, and disk errors cause it too, so do not replace memory until the test confirms it.

Can a driver update fix it?

Often yes. Many cases come from an outdated or mismatched driver. Updating from the maker's site, or rolling back a recent driver, resolves a large share of these crashes.

Should I worry if it only happened once?

A single occurrence may be a random glitch. Keep using the PC and watch for a pattern. If it returns, run the memory, disk, and file checks to find the cause before it gets worse.