Kernel Security Check Failure: How to Fix It in Minutes

You’re in the middle of something important — an assignment, a work call, a competitive game — and your screen suddenly flashes white, shows a sad face, and reboots. That’s the Kernel Security Check Failure BSOD (Blue Screen of Death) on Windows 11, and it’s more common than you think.

This error occurs when Windows detects that a critical memory structure has become corrupted. To prevent permanent damage, the system immediately shuts itself down.

In this guide, you will find 10 practical solutions—ranging from the fastest ‘one-click’ fixes to deep, system-level repairs. Let’s get rid of this error.

Quick Checks — Try These First

• Restart your PC — this immediately fixes temporary memory corruption.
• Disconnect all external USB devices and peripherals, then reboot.
• Check for Windows Updates — Microsoft fixed GPU-related BSODs in February 2026 (Build 26200.7840+).
• Run a quick antivirus scan — malware can corrupt kernel data structures.
• To check if a third-party app is causing crashes, boot into Safe Mode.
• Undo any recent software installs or driver updates from the last 24 hours.

What is Kernel Security Check Failure?

Definition: Kernel Security Check Failure (stop code 0x00000139) is a Windows BSOD error that triggers when the OS kernel detects corruption in a critical system data structure or memory area. Windows stop working immediately to stop further damage to your PC.

Think of the kernel as the brain of your operating system. It controls memory, hardware, and core processes 24/7. When it finds something broken — like a corrupted driver or bad RAM — it throws up this error.

On Windows 11 version 24H2 and later, the crash screen appears black instead of the traditional blue background. The stop code and message remain the same.

Why Does This Happen?

• Outdated or incompatible graphics/GPU drivers (the most common cause)
• Corrupted Windows system files or registry entries
• Faulty or failing RAM
• Malware or virus infections interfering with Kernel processes
• A defective Windows update (specifically the dxgmms2.sys GPU bug introduced in early 2026)
• An overclocked CPU or GPU that becomes unstable under heavy load
• Recently installed software conflicting with Windows Kernel security

Step- By Step Fixes For Kernel Security Check Failure

1. Update Windows to the Latest Build

In early 2026, a confirmed bug led to a “Kernel Security Check Failure” issue involving the dxgmms2.sys graphics file. Microsoft resolved this issue in Build 26200.7840. Installing the latest update often resolves this problem immediately.

• Press Windows + I to open Settings
• Click Windows Update in the left panel
• Click Check for updates and install all pending updates
• Restart your PC

2. Update or Roll Back Your Graphics Driver

The primary cause of this BSOD is GPU drivers. An outdated or recently corrupted driver update can corrupt kernel memory and trigger a crash.

• Right-click Start → Device Manager
• Expand Display Adapters → right-click your GPU
• Choose Update driver → Search automatically
• If it just updated, choose Roll Back Driver instead

Warning: If Device Manager shows a yellow exclamation mark on any device, fix that driver first — it is very likely the offender.

3. Run SFC Scan to Repair System Files

The System File Checker (SFC) scans all protected Windows files and repairs corrupted ones automatically. This is one of the most reliable fixes for kernel errors.

• Press Windows + S → type cmd
• Right-click Command Prompt → Run as administrator
• Type the command below and press Enter
• Wait for the scan to complete (takes 5–10 minutes)
• Restart your PC

sfc /scannow

4. Run DISM to Repair the Windows Image

If SFC detects an issue but is unable to fix it, DISM goes deeper to repair the Windows Component Store itself. For best results, always run DISM after SFC.

• Open Command Prompt as administrator
• Run the following command
• Wait for it to finish — it may take 10–20 minutes
• Restart your PC.

DISM /Online /Cleanup-Image /RestoreHealth

5. Run Windows Memory Diagnostic 

Faulty RAM is a very common cause of this error. Windows has a built-in tool to test your memory for hardware faults.

• Press Windows + S → type Windows Memory Diagnostic
• Click Restart now and check for problems
• Your PC will restart and run the test automatically
• Results appear after the next boot in the notification area

Warning: If errors are detected, one of your RAM sticks may be physically faulty and needs replacement.

6. Boot into Safe Mode and Test for Stability

Safe Mode loads only essential Windows drivers. If the BSOD stops occurring in Safe Mode, a third-party driver or app is almost certainly the cause of the crash.

• Press Windows + I → System → Recovery
• Under Advanced startup, click Restart now
• Choose Troubleshoot → Advanced options → Startup Settings
• Press 4 or F4 to enter Safe Mode
• Use your PC normally — if stable, a third-party app is the cause

7. Run a Full Malware Scan

Viruses and malware can directly corrupt kernel-level memory structures. To resolve this issue, perform a scan using Windows Defender or Malwarebytes.

• Press Windows + I → Privacy & Security → Windows Security
• Click Virus & threat protection
• Choose Full scan → click Scan now
• Remove any threats found and restart

8. Check Your Disk for Errors (CHKDSK)

Kernel errors can occur due to a failing hard drive or an SSD with bad sectors. CHKDSK scans your drive and automatically fixes logical errors.

• Open Command Prompt as administrator
• Type the command below and press Enter
• Type Y and restart — the scan runs before Windows loads

chkdsk C: /f /r

9. Disable Overclocking Settings

If you have overclocked your CPU or GPU, instability under load can directly lead to a kernel crash. Reverting to the default clock speeds often resolves this issue immediately.

• Restart your PC and enter BIOS/UEFI (usually press Del or F2 on startup)
• Find the Overclocking or Performance settings
• Choose Load Optimized Defaults or set CPU/RAM to base speed
• Save and exit

10. Perform a System Restore

If the BSOD started occurring after a specific event—such as installing a new app or an update—you can fix everything in a single step by reverting to a ‘restore point’ from before that event.

• Press Windows + S → type Create a restore point
• Click System Restore → Next
• Select a restore point from before the error started
• Click Finish and let the process complete

Warning: This does not affect your personal files, but recently installed apps or drivers may be removed.

How to Prevent This ?

• Keep Windows updated — Microsoft regularly fixes kernel-level bugs.
• Always update your GPU and motherboard drivers exclusively from the official manufacturer’s website.
• Run SFC /scannow every month to detect file corruption, allowing you to fix potential issues before they lead to a BSOD.
• Avoid excessive overclocking unless you have adequate cooling and facilities for stability testing.
• Create a System Restore point before installing any major software or driver updates.
• Run a memory test (such as MemTest86 or Windows Memory Diagnostic) every 6–12 months.

Best Practices

If you get this BSOD repeatedly after a Windows update, check Windows Update History and use the "Uninstall updates" option to roll back the specific patch causing the crash. Microsoft patches the patch quickly.

Use free tool WhoCrashed or Windows Event Viewer to read your minidump files. These files tell you exactly which driver file triggered the BSOD — so you skip guesswork entirely.

If the 'dxgmms2.sys' error appears on your crash screen, the solution is simple—update Windows to Build 26200.7840 or a newer version. Microsoft confirmed this specific GPU BSOD in February 2026 and released a patch to fix it.

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