Windows Blue Screen (BSOD) Error Codes — How to Fix Them

What Is a Blue Screen of Death (BSOD)?

A BSOD occurs when Windows encounters a critical error it cannot recover from. The system halts and displays a blue screen with an error code. Understanding the error code is the first step to fixing the problem.

CRITICAL_PROCESS_DIED (0x000000EF)

This error means an essential Windows process stopped unexpectedly.

How to Fix

1. Boot into Safe Mode — Restart your PC and press F8 repeatedly. Select Safe Mode with Networking.
2. Run SFC scan — Open Command Prompt as Administrator and run sfc /scannow.
3. Run DISM — If SFC finds issues, run DISM /Online /Cleanup-Image /RestoreHealth.
4. Check for driver updates — Open Device Manager and look for devices with yellow warning icons.
5. Uninstall recent software — If the error started after installing new software, remove it.

IRQL_NOT_LESS_OR_EQUAL (0x0000000A)

This is usually caused by a faulty driver trying to access memory it should not.

How to Fix

1. Update drivers — Especially graphics, network, and chipset drivers. Download from the manufacturer website.
2. Disable overclocking — Reset BIOS to default settings if you have overclocked your CPU or RAM.
3. Test RAM — Run Windows Memory Diagnostic by typing mdsched.exe in the Start menu.
4. Check recently installed drivers — Roll back any driver updated before the error started.

KERNEL_SECURITY_CHECK_FAILURE (0x00000139)

This error indicates a kernel-level security check failed, often related to corrupted files or incompatible drivers.

How to Fix

1. Run SFC and DISM — Same as above: sfc /scannow followed by the DISM command.
2. Update Windows — Go to Settings > Windows Update and install all pending updates.
3. Check disk health — Run chkdsk C: /f /r in an elevated Command Prompt.
4. Reinstall drivers — Uninstall and reinstall your display and storage drivers.

SYSTEM_SERVICE_EXCEPTION (0x0000003B)

A system service encountered an exception, typically caused by a buggy driver or corrupted system file.

How to Fix

1. Identify the faulty driver — Check the BSOD details for a driver name (e.g., nvlddmkm.sys for Nvidia).
2. Update or rollback the driver — In Device Manager, right-click the device and choose Update Driver or Roll Back.
3. Disable antivirus temporarily — Third-party antivirus can sometimes trigger this error.
4. Run System File Checker — Execute sfc /scannow from Command Prompt.

PAGE_FAULT_IN_NONPAGED_AREA (0x00000050)

Windows tried to access a memory page that was not available. Often caused by faulty RAM or corrupted drivers.

How to Fix

1. Test your RAM — Run Windows Memory Diagnostic or download MemTest86 for a thorough test.
2. Check virtual memory settings — Go to System Properties > Advanced > Performance Settings > Advanced > Virtual Memory.
3. Update storage drivers — Especially if you recently changed or added a drive.
4. Disable fast startup — Go to Control Panel > Power Options > Choose what the power buttons do > Uncheck "Turn on fast startup."

General BSOD Prevention Tips

• Keep Windows and all drivers up to date
• Do not install drivers from unknown sources
• Monitor system temperatures to prevent overheating
• Run regular disk health checks with chkdsk
• Consider using a reliable antivirus to prevent malware-related crashes — see our Best Antivirus picks
• Back up your data regularly in case a BSOD leads to data loss