Microsoft Stop Code (Blue Screen of Death): Complete Fix Guide for All BSOD Errors

Understanding Microsoft Stop Codes

A Microsoft stop code — colloquially known as the Blue Screen of Death (BSOD) or, in newer Windows versions, sometimes a Green Screen of Death — is Windows' last-resort mechanism to prevent system damage when a fatal, unrecoverable error occurs. The system halts all operations, dumps memory to disk, and displays a stop code that identifies the type of failure.

Modern Windows 10 and 11 BSODs display a sad face emoji, a brief description, a QR code you can scan to visit https://www.microsoft.com/en-us/safety for more information, and the stop code itself (e.g., KERNEL_SECURITY_CHECK_FAILURE). Older formats show 0x-prefixed hexadecimal codes like 0x0000000A.

Most Common Microsoft Stop Codes and Their Meanings

• 0xC000021A / 0xC00021A / Stop Code 21A — A critical user-mode subsystem (winlogon.exe or csrss.exe) has failed. Often triggered by corrupted system files, mismatched DLLs after an update, or third-party security software conflicts.
• BAD_POOL_CALLER (0x000000C2) — A process requested invalid memory pool allocation. Usually caused by a buggy driver or corrupted memory.
• IRQL_NOT_LESS_OR_EQUAL / DRIVER_IRQL_NOT_LESS_OR_EQUAL (0x0000000A / 0x000000D1) — A driver or process attempted to access a memory address at an inappropriate IRQL (interrupt request level). Frequently tied to network adapter, GPU, or disk controller drivers.
• KERNEL_SECURITY_CHECK_FAILURE (0x00000139) — Windows Kernel detected data structure corruption. Causes include faulty RAM, outdated drivers, or malware.
• INACCESSIBLE_BOOT_DEVICE (0x0000007B) — Windows cannot access the partition containing the OS at boot. Triggered by storage driver changes, corrupted BCD, or a failing SSD/HDD.
• MEMORY_MANAGEMENT (0x0000001A) — Indicates a serious problem with Windows memory management. Often hardware RAM or paging file corruption.
• DRIVER_POWER_STATE_FAILURE (0x0000009F) — A driver failed to handle a power state transition (sleep/hibernate/resume). Usually caused by outdated device drivers.

Step 1: Capture and Identify Your Stop Code

Before you can fix anything, you need the exact stop code. If your system reboots too quickly:

1. Go to Control Panel → System → Advanced System Settings → Startup and Recovery → Settings.
2. Uncheck Automatically restart under System Failure.
3. The next BSOD will pause so you can read the stop code.

Alternatively, analyze the saved minidump:

• Dump files are saved to C:\Windows\Minidump\ (small memory dumps) or C:\Windows\MEMORY.DMP (full dump).
• Use WinDbg (from the Windows SDK) or the free WhoCrashed tool to analyze them.
• In WinDbg, run: !analyze -v after opening the dump file.

You can also search the Windows Event Log:

1. Press Win + R, type eventvwr.msc, hit Enter.
2. Navigate to Windows Logs → System.
3. Filter for Critical and Error events around the time of the BSOD.

Step 2: Boot Into Safe Mode

If Windows won't boot normally, access Safe Mode:

• From Settings: Settings → Update & Security → Recovery → Advanced Startup → Restart Now → Troubleshoot → Advanced Options → Startup Settings → Restart → Press 4 for Safe Mode.
• From a bootloop: Windows will automatically enter the Recovery Environment (WinRE) after 2–3 failed boots. Choose Troubleshoot → Advanced Options → Startup Settings.
• With installation media: Boot from a Windows USB/DVD, choose Repair your computer, then navigate to Advanced Options.

Step 3: Repair System Files with SFC and DISM

This is the first actionable fix for most stop codes, especially 0xC000021A and MEMORY_MANAGEMENT.

Open an elevated Command Prompt (right-click Start → Command Prompt (Admin)) and run:

sfc /scannow

If SFC reports errors it cannot fix, run DISM to repair the Windows image first:

DISM /Online /Cleanup-Image /CheckHealth
DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /RestoreHealth

Then rerun sfc /scannow. Reboot after completion.

Step 4: Roll Back or Update Drivers

For stop codes like IRQL_NOT_LESS_OR_EQUAL, DRIVER_IRQL_NOT_LESS_OR_EQUAL, DRIVER_POWER_STATE_FAILURE, and KERNEL_SECURITY_CHECK_FAILURE:

1. Boot into Safe Mode.
2. Open Device Manager (Win + X → Device Manager).
3. Look for devices with a yellow warning icon.
4. Right-click the suspect device (often GPU, network adapter, or storage controller) → Properties → Driver → Roll Back Driver.
5. If Roll Back is grayed out, right-click → Update Driver and search automatically.

For GPU drivers specifically, use DDU (Display Driver Uninstaller) in Safe Mode to cleanly remove the old driver before installing a fresh copy from the manufacturer's website.

Step 5: Check RAM with Windows Memory Diagnostic

For BAD_POOL_CALLER and MEMORY_MANAGEMENT stop codes:

1. Press Win + R, type mdsched.exe, hit Enter.
2. Choose Restart now and check for problems.
3. The tool runs automatically and reports errors on next login.

For deeper testing, use MemTest86 (bootable USB), which runs outside Windows and is more thorough.

Step 6: Fix INACCESSIBLE_BOOT_DEVICE

This stop code requires working with the BCD (Boot Configuration Data) and storage drivers:

1. Boot from Windows installation media.
2. Choose Repair your computer → Troubleshoot → Advanced Options → Command Prompt.
3. Run:

bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd

4. If that doesn't help, ensure storage controller drivers (NVMe/SATA) are present by checking BIOS settings — switching from RAID to AHCI mode or vice versa can cause this error.

Step 7: Uninstall a Problematic Windows Update

If the BSOD started immediately after a Windows Update:

1. Go to Settings → Update & Security → View Update History → Uninstall Updates.
2. Sort by Installed On date.
3. Uninstall the most recent Cumulative Update or driver update.
4. Alternatively, use WinRE: Troubleshoot → Advanced Options → Uninstall Updates.

Step 8: Microsoft Surface-Specific BSOD Fixes

For Microsoft Surface Blue Screen issues (Surface Pro, Surface Book, Surface Laptop):

1. Perform a two-button shutdown: Hold Power + Volume Down for 15 seconds until the Surface logo appears twice.
2. Update Surface firmware via Settings → Windows Update — Surface firmware is delivered via Windows Update.
3. Visit the Microsoft Surface Recovery Image page to download and restore the original factory image if all else fails.
4. For Surface-specific driver issues, download the Surface Update Tool from Microsoft's official site.

Step 9: Microsoft Teams Blue Screen

A recurring BSOD caused specifically when using Microsoft Teams is often related to GPU driver issues with hardware acceleration:

1. Open Teams → Settings → General → Disable GPU hardware acceleration.
2. Update your GPU driver.
3. Check for Teams updates: Profile icon → Check for updates.

Step 10: Last Resort — Reset Windows

If all other steps fail:

1. Go to Settings → Update & Security → Recovery → Reset this PC.
2. Choose Keep my files or Remove everything.
3. Follow the on-screen instructions.

For completely unbootable systems, use a Windows 10/11 installation USB and choose Reset this PC from WinRE.