How to Fix: KERNEL_SECURITY_CHECK_FAILURE (Stop Code 0x139)

Quick Fix

Fastest fix to try first:

1. Restart your PC — if it only happened once, it may have been a one-off glitch.
2. If it keeps happening and you’re playing a game with anti-cheat (like Easy Anti-Cheat), uninstall and reinstall the anti-cheat service via the game’s install folder — this resolves a large share of cases.
3. If it happens outside of gaming, go to Settings > Windows Update > Check for updates and install everything, then restart.

Step-by-Step Guide

What KERNEL_SECURITY_CHECK_FAILURE Means

KERNEL_SECURITY_CHECK_FAILURE is a Windows Blue Screen of Death (BSOD) stop code, often shown with the code 0x139. It is a Windows stop code error that appears when the operating system detects corruption in critical system memory or internal data structures. The kernel is the core component of Windows responsible for managing hardware, memory, and essential processes, and as part of its normal operation it continuously validates critical system data — if it detects corruption, it triggers a system bug check, causing Windows to halt to prevent further damage.

On the technical side, Microsoft’s own driver documentation states that the KERNEL_SECURITY_CHECK_FAILURE bug check has a value of 0x00000139, and indicates that the kernel detects the corruption of a critical data structure. This can include things like a corrupted linked list, a damaged kernel synchronization object, or a stack-based buffer overrun — details that are mostly relevant to advanced debugging.

On newer systems, note that on newer versions of Windows 11, particularly those running version 24H2 and later, the crash screen may appear black instead of blue, so don’t be confused if you see a black screen instead of the classic blue one.

Common Causes

This error can stem from several different sources, which is why troubleshooting works best in order from simple to advanced:

1. Buggy or outdated drivers — drivers are the intermediaries between the operating system and hardware components, and if one is buggy, outdated, or incompatible, it can start doing things it shouldn’t, like accessing memory it’s not supposed to.
2. Kernel-level anti-cheat software — games with kernel-level anti-cheat can trigger BSODs if their drivers misbehave, and Easy Anti-Cheat in particular is frequently reported as a trigger.
3. Corrupted system files — often from an incomplete update or improper shutdown.
4. Faulty or incompatible RAM — incompatible or faulty hardware, especially RAM or a hard drive, can trip up the kernel and cause the error.
5. Overclocking — pushing your CPU or GPU past its factory limit increases power consumption and heat, increasing the likelihood of a kernel security check failure.
6. Malware — rare, but malware can infect operating systems and interfere with system files, and in rare cases some malware strains specifically target the Windows kernel.
7. A known Windows 11 GPU bug (patched) — one recent report noted that KERNEL_SECURITY_CHECK_FAILURE was most commonly triggered by incompatible drivers, anti-cheat software, or a specific GPU bug related to dxgmms2.sys, which Microsoft confirmed and patched in a later Windows 11 build — so keeping Windows updated matters.

Step-by-Step Fix

1. Rule out recent changes first

If you added new hardware before the errors started, remove it and reconnect the previous hardware to see if the issue goes away — if it does, the new component may be faulty. Also check Settings > Apps > Apps & features, sort by install date, and uninstall anything suspicious you added recently (especially games with anti-cheat or low-level system utilities).

2. If it happens during a specific game (Easy Anti-Cheat, BattlEye, etc.)

This is one of the most commonly reported triggers. Try:

1. Navigate to the game’s install folder (e.g., SteamsteamappscommonGameNameEasyAntiCheat), run the setup executable, and choose Repair Service, or fully uninstall and let the game reinstall it.
2. If you use third-party antivirus, temporarily disable it — some users have found their antivirus software was mistakenly flagging the anti-cheat as malware, and disabling it resolved the crashes.
3. Ensure Windows and your GPU drivers are fully updated, since a support agent noted this software is known to cause system crashes and recommended ensuring BIOS and Windows are fully up to date before reinstalling the anti-cheat.

3. Boot into Safe Mode to isolate the cause

Start Windows in safe mode, which disables secondary drivers and system files and runs the computer on basic factory settings — if the error disappears in safe mode, the system hardware and primary drivers are probably fine. To do this: hold Shift while clicking Restart, then go to Troubleshoot > Advanced options > Startup Settings > Restart, and press 4 for Safe Mode.

4. Update or roll back drivers (Windows)

In Safe Mode or normal mode, open Device Manager and look for devices with a yellow exclamation mark; for any such device, right-click and choose Update driver, and if issues persist, disable or uninstall the device and test again. If the crashes started right after a driver update, roll back that recently updated device driver to a previous version.

5. Try turning off Memory Integrity / Core Isolation (Windows 11)

This is a Windows 11–specific setting that can conflict with older or unsigned drivers. Go to Settings > Privacy & Security > Windows Security, click Device Security, then Core isolation details, and turn off Memory integrity (also called Kernel-mode Hardware-enforced Stack Protection), then restart the PC. If the crashes stop, the culprit is an incompatible driver that needs updating before you re-enable this security feature.

6. Run system file and disk repairs

Open an elevated Command Prompt and run these in order:

1. sfc /scannow — if SFC finds and fixes any corrupted files, restart your PC to apply the repairs.
2. DISM /Online /Cleanup-Image /RestoreHealth (or CheckHealth/ScanHealth) for a deeper image repair.
3. chkdsk C: /f (replace C with your system drive letter) to check for and repair disk errors — this can take 30 minutes to 2 hours.

7. Test your RAM

Faulty memory is a common culprit. Press Win + R, type mdsched.exe, and select Restart now and check for problems. The Memory Diagnostic tool will run a stress test of your system memory, and if any issues are detected, you’ll need to consider replacing your system memory. For a more thorough test, a third-party tool like Memtest86+ run overnight can catch intermittent errors the built-in tool misses.

8. Rule out malware

Run a full scan with Windows Security (or your preferred antivirus), and optionally a second-opinion scanner. This is quick and low-risk, though in practice malware is rarely the actual cause.

9. Check for a pending Windows or BIOS update

Go to Settings > Windows Update > Check for updates and install everything. Also check your motherboard/laptop manufacturer’s site for a newer BIOS/UEFI version, since ensuring BIOS/UEFI firmware is up to date from the system/motherboard vendor has resolved this error for some users, particularly after a Windows feature update.

10. Undo overclocking

Revert your processor, graphics card, or RAM to their intended speeds to see if this solves the issue, including disabling XMP/EXPO RAM profiles in BIOS if enabled.

11. When to escalate to advanced or professional help

If you’re comfortable with advanced tools, install Debugging Tools for Windows (WinDbg), copy the memory dump file to a stable machine, open it in WinDbg, and analyze the stack to identify the failing driver or component. If none of the above resolves it:

1. Try a System Restore to a point before the crashes began.
2. As a last resort, back up your data and perform a Reset this PC (Settings > System > Recovery) or a clean Windows reinstall.
3. If crashes persist after a clean install, or you suspect a specific piece of hardware (especially RAM, SSD/HDD, or motherboard), it’s time to run manufacturer hardware diagnostics or consult a PC repair technician — repeated BSODs surviving a full OS reinstall usually point to failing hardware rather than software.

Platform note: This entire error and all fixes above are specific to Windows (10 and 11); it does not occur on macOS, consoles, or mobile operating systems.