What does Windows error code 5085 (ERROR_CLUSTER_GUM_NOT_LOCKER) mean?

ERROR_CLUSTER_GUM_NOT_LOCKER

A non locker code got a request to reserve the lock for making global updates.

ERROR_CLUSTER_GUM_NOT_LOCKER is Win32 error 5085 (0x13DD) and belongs to Failover clustering Global Update Manager lock ownership.

Troubleshooting steps

• Record requesting node and component.
• Record GUM lock owner and update sequence.
• Record cluster log call path.
• Record membership changes and concurrent configuration writes.

What to verify

Verify whether code that does not own the GUM lock attempted to reserve it for a global update. Check requesting node and component together with GUM lock owner and update sequence.

Handling, retry, and recovery

Preserve cluster logs and correct the component or sequence that issued the non-owner request; repeated global updates can worsen configuration divergence.

Practical example

A rare internal race sends a reserve request from a non-locker path.

References

• Microsoft: System Error Codes (4000–5999) — reference for error 5085.
• Microsoft: Failover clustering documentation — reference for error 5085.
• Microsoft: Get-ClusterLog — reference for error 5085.
• Microsoft: Troubleshoot unexpected cluster failover — reference for error 5085.