What does Windows error code 6644 (ERROR_LOG_PINNED) mean?

ERROR_LOG_PINNED

Log space cannot be reclaimed because the log is pinned.

ERROR_LOG_PINNED is Win32 error 6644 (0x000019F4) and concerns CLFS log-space reclamation blocked by pinned records.

Where the result appears

• handling a log-full condition.
• shrinking a log.
• removing old containers.
• advancing the base log after checkpoint or archive.

What to verify

Verify whether all records below the proposed base log sequence number are no longer required by any client. Check oldest required LSN for every client, base LSN and last flushed LSN, and restart-area ownership.

Likely causes

• a client has not advanced its base LSN.
• an outstanding restart area still references old records.
• archive progress has not released the range.
• a failed or hung client retains a reservation or pin.
• management attempts reclamation before dependent state is durable.

Troubleshooting steps

1. Collect oldest required LSN for every client.
2. Record base LSN and last flushed LSN.
3. Correlate restart-area ownership with the owning application log, CLFS-related System events, storage events, and any transaction or recovery trace.

Handling, retry, and recovery

Identify the client that owns the oldest required record, complete its checkpoint or archive, advance its base LSN, and let CLFS reclaim space without deleting container files manually.

Related errors

ERROR_LOG_PINNED_RESERVATION identifies reservations as the dominant reason for the pin; this code can also result from active recovery or restart records.

Example

A service stops checkpointing after a worker failure. CLFS cannot recycle the oldest container because that client still advertises an old base LSN; restarting the worker and completing a checkpoint releases the range.

References

• Microsoft: Win32 system error range containing this code
• Microsoft: Common Log File System
• Microsoft: Creating a Log File
• Microsoft: Introduction to CLFS