0x0000009B is a storage-related stop code result. This bug check indicates that a problem occurred in the UDF file system.
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 problem occurred in the UDF file system.
UDFS_FILE_SYSTEM identifies a stop-code family. The four bug-check parameters and dump, if available, help distinguish the actual failure path.
| Code | 0x0000009B |
|---|---|
| Short hex form | 0x9B |
| Symbol | UDFS_FILE_SYSTEM |
| Windows family | Blue screen and stop codes |
| Source level | Microsoft bug-check page |
Microsoft’s technical cause notes add: The UDFS_FILE_SYSTEM bug check might be caused disk corruption. Corruption in the file system or bad blocks (sectors) on the disk can induce this error. Corrupted SCSI and IDE drivers can also adversely affect the system's ability to read and write to the disk and…
Safe next steps
- For 0x0000009B (UDFS_FILE_SYSTEM), protect important files first. Record whether the boot drive is detected and whether the same code follows an I/O error.
- Use the Microsoft bug-check parameters and the exact drive or PC maker’s diagnostics before attempting disk repair.
- Stop write-heavy repairs if the drive disappears or repeated read errors occur.
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.
Stop repeated write-heavy scans or repairs if the drive drops offline or important data is not backed up.
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.