0x0000008B is a kernel/debugger stop code result. This bug check indicates that a mismatch has occurred in the MBR checksum.
Code reference and safe checks
Read the exact screen and operation before selecting a repair. This page does not run commands or collect files, keys or logs.
What this value means
This bug check indicates that a mismatch has occurred in the MBR checksum.
MBR_CHECKSUM_MISMATCH identifies a stop-code family. The four bug-check parameters and dump, if available, help distinguish the actual failure path.
| Code | 0x0000008B |
|---|---|
| Short hex form | 0x8B |
| Symbol | MBR_CHECKSUM_MISMATCH |
| Windows family | Blue screen and stop codes |
| Source level | Microsoft bug-check page |
Microsoft’s technical cause notes add: The MBR_CHECKSUM_MISMATCH bug check occurs during the boot process when the MBR checksum that the Microsoft Windows operating system calculates does not match the checksum that the loader passes in.
The linked debugger page also describes its parameters: The MBR_CHECKSUM_MISMATCH bug check occurs during the boot process when the MBR checksum that the Microsoft Windows operating system calculates does not match the checksum that the loader passes in.
Safe next steps
- For 0x0000008B (MBR_CHECKSUM_MISMATCH), record the exact stop code and parameters. Microsoft’s debugger reference may describe a kernel condition rather than a consumer fix.
- If crashes repeat, inspect the dump locally with official WinDbg and compare its parameters with this code’s Microsoft page.
- Do not enable Driver Verifier or change firmware as a generic first step; ask qualified support if the PC cannot start.
After one step, repeat the original operation and record whether this same code returns. A different code needs a fresh interpretation.
What this code cannot prove
The source establishes the identifier and reference meaning. It does not establish the cause on your specific PC.
If Windows no longer starts or the issue repeats with hardware warnings, protect files and use manufacturer or qualified support.
Official reference and verification
Source type: Microsoft bug-check page. Checked against the source set on Nov 2, 2026.
The reference gives the meaning of this identifier. It does not inspect your PC or guarantee that one repair will work.