VSS Writer Failure Diagnostic and Repair Guide
Find which Volume Shadow Copy (VSS) writers have failed and get read-only checks plus clearly labelled repair steps for the service behind each one. Useful when backups from Commvault, Veeam, Cohesity or Windows Server Backup fail on a VSS writer error.
How to read vssadmin list writers
Each writer block shows a State and a Last error. A healthy writer shows State: [1] Stable and Last error: No error. States [2] to [5] are normal while a backup is running; if no backup is running, the writer is stuck. States [6] to [12] mean the writer failed at that step of the backup sequence (see Microsoft’s VSS_WRITER_STATE reference).
Common Last error values: Inconsistent shadow copy (0x800423F0), Out of resources (0x800423F1), Timed out (0x800423F2), Retryable error (0x800423F3), Non-retryable error (0x800423F4).
Each writer runs inside a Windows or application service. Many writer failures clear after restarting the writer’s service. If the writer is still failed afterwards, a reboot in a maintenance window is the reliable fix. Microsoft lists the built-in writers and their services in In-Box VSS Writers.
Estimates and generated commands are a starting point. Review and test before running in production.
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