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# fault

The fault log level.

```
static let fault: OSLogType
```

## Discussion

Logging a message at this level is equivalent to calling the [`os_log_fault`](/documentation/os/os_log_fault) function. Use this level only to capture system-level or multiprocess information when reporting system errors.

The system always writes fault-level messages to the data store. They remain in the store until its size exceeds its storage quota, at which point, the system purges the oldest messages in the store to free up space. If an activity object exists, logging at this level captures information for the entire process chain.

---

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