0x000000A4 is a storage-related stop code result. This bug check indicates that a problem occurred in the CNSS file system filter.
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 CNSS file system filter.
CNSS_FILE_SYSTEM_FILTER identifies a stop-code family. The four bug-check parameters and dump, if available, help distinguish the actual failure path.
| Code | 0x000000A4 |
|---|---|
| Short hex form | 0xA4 |
| Symbol | CNSS_FILE_SYSTEM_FILTER |
| Windows family | Blue screen and stop codes |
| Source level | Microsoft bug-check page |
Microsoft’s technical cause notes add: The CNSS_FILE_SYSTEM_FILTER bug check might occur because nonpaged pool memory is full. If the nonpaged pool memory is completely full, this error can stop the system. However, during the indexing process, if the amount of available nonpaged pool memory is very low,…
Safe next steps
- For 0x000000A4 (CNSS_FILE_SYSTEM_FILTER), 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.