ErrorFindly
0x0000008BBSODCritical

0x0000008B — MBR Checksum Mismatch | Blue Screen Fix Guide

MBR_CHECKSUM_MISMATCH

Windows XPWindows VistaWindows 7Windows 8Windows 10Windows 11

What Does 0x0000008B Mean?

The Master Boot Record (MBR) checksum does not match, indicating the MBR has been modified unexpectedly.

Real-World Causes

  1. 1Boot sector virus or malware
  2. 2Corrupted MBR
  3. 3Disk tool modifying boot sector
  4. 4Multi-boot software conflict

Symptoms

  • ⚠Blue screen with stop code MBR_CHECKSUM_MISMATCH
  • ⚠System reboots unexpectedly
  • ⚠Possible data loss from unsaved work

DIY Fix

Beginner-friendly steps you can try at home

  1. 1Restart your computer
  2. 2Use Windows Recovery Environment
  3. 3Run Startup Repair
  4. 4Rebuild BCD with bootrec commands

Advanced Fix

For experienced users and IT professionals

  1. 1Rebuild BCD store manually
  2. 2Use bcdedit to verify boot configuration
  3. 3Repair Master Boot Record with bootrec /fixmbr
  4. 4Reinstall Windows if boot files are corrupted

Frequently Asked Questions

What causes MBR_CHECKSUM_MISMATCH?
The Master Boot Record (MBR) checksum does not match, indicating the MBR has been modified unexpectedly.
Can I fix MBR Checksum Mismatch myself?
In many cases yes. Start with basic troubleshooting like restarting, updating drivers, and running System File Checker. If the issue persists, advanced analysis of crash dumps may be needed.

Related Error Codes

0x0000007BInaccessible Boot Device0x000000EDUnmountable Boot Volume

About the Author

Windows Troubleshooting Team

Verified against official Microsoft documentation and real-world diagnostic data. Error behavior confirmed across Windows 10, Windows 11, and Windows Server.