What does Windows error code 4445 (ERROR_SMR_GARBAGE_COLLECTION_REQUIRED) mean?

ERROR_SMR_GARBAGE_COLLECTION_REQUIRED

The volume must undergo garbage collection.

ERROR_SMR_GARBAGE_COLLECTION_REQUIRED is Win32 error 4445 (0x115D) and belongs to host-managed SMR volume maintenance.

Where the result appears

• Writes to a shingled magnetic recording volume.
• Filesystem allocation on host-managed zoned media.
• Storage maintenance monitoring zone utilization.
• A workload that has exhausted writable zones without reclamation.

Likely causes

• obsolete data occupies zones that must be reclaimed sequentially.
• the volume lacks enough clean zones for the requested write pattern.
• garbage collection was deferred under sustained workload.
• storage policy or firmware cannot keep up with random overwrites.

Troubleshooting steps

• Record device model, SMR mode, firmware, and volume.
• Record zone state, free zones, and garbage-collection telemetry.
• Record write workload and latency trend.
• Record storage health events and temperature.
• Record maintenance windows and available capacity.

What to verify

Verify whether obsolete data occupies zones that must be reclaimed sequentially. Check device model, SMR mode, firmware, and volume together with zone state, free zones, and garbage-collection telemetry.

Handling, retry, and recovery

Allow or initiate the supported garbage-collection process, reduce write pressure, and confirm healthy zone reclamation before resuming the workload. Do not treat host-managed SMR like unconstrained random-write media.

Difference from nearby codes

The code requests media-specific maintenance; it is not equivalent to ordinary filesystem free-space exhaustion.

Practical example

A log workload rewrites many small regions until clean zones run low.

References

• Microsoft: System Error Codes (4000–5999) — reference for error 4445.
• Microsoft: Storage management — reference for error 4445.
• Microsoft: Troubleshoot data corruption and disk errors — reference for error 4445.