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VSS_E_WRITER_STATUS_NOT_AVAILABLE
VSS_E_WRITER_STATUS_NOT_AVAILABLE is the failure HRESULT 0x80042409 (signed decimal -2147212279, unsigned decimal 2147755017). Its severity bit is set, the facility field is 4 (FACILITY_ITF), and the facility-specific code is 0x2409.
One or more VSS writer statuses are unavailable. A requester asked VSS for writer status, but status cannot be supplied for at least one participating writer. AllStat notes that a writer may have reached the limit of available backup/restore session states.
AllStat records the official condition as: “Writer status is not available for one or more writers. A writer may have reached the limit to the number of available backup-restore session states.” This wording should be interpreted at the VSS/ASR stage described below, not as a generic disk or COM failure.
Where VSS_E_WRITER_STATUS_NOT_AVAILABLE appears
This result belongs to writer coordination, not ASR disk mapping. It can appear after GatherWriterStatus or while old, incomplete backup and restore sessions still occupy limited writer state.
Likely causes
- A requester did not complete the normal cleanup sequence for earlier backup or restore sessions.
- Overlapping operations consume all session-state objects maintained for a writer.
- A writer or backup product leaves abandoned state after cancellation or failure.
- The status query is issued at the wrong point or without waiting for the asynchronous gather operation.
Evidence to capture before changing storage
- Record writer class ID, instance ID, name and state for every writer that can still be queried.
- Capture the complete requester lifecycle, including BackupComplete, PostRestore, OnAbort and final status gathering.
- Correlate Application log VSS events with active and recently terminated backup jobs.
- Preserve the HRESULT from the first unavailable writer instead of reporting only a global backup failure.
Diagnostic sequence
- Verify that
GatherWriterStatuscompleted before calling status accessors. - Look for concurrent backup products or overlapping jobs using the same writer.
- Check whether failed sessions were explicitly aborted and finalized.
- Compare intermittent garbage-collection events with a consistently reproducible active-session failure.
Recovery and retry
Allow transient sessions to drain, stop overlapping operations, and retry once. If the condition repeats, correct the requester cleanup sequence or repair the affected writer/application rather than continuously restarting VSS services.
What this HRESULT does not prove
The code does not automatically mean the writer process crashed or its data is inconsistent. Status may be unavailable because session bookkeeping is exhausted even when the current writer is otherwise healthy.
Difference from nearby VSS results
VSS_E_WRITER_NOT_RESPONDING indicates failure to answer a status gather. This HRESULT specifically says status is unavailable and may be caused by session-state limits.
Practical example
A test harness repeatedly abandons restore sessions before PostRestore cleanup. A later backup reaches the writer session limit and receives this code until old session state is released.
Guidance for backup software and telemetry
Requester implementations should log lifecycle completion and guarantee cleanup in error paths. A bounded delayed retry is reasonable; an immediate infinite retry can create more abandoned sessions.
A useful support record includes the operation phase, backup set or restore session identifier, recovery-environment version, firmware mode, exact disk identities, source and target capacities, online/exclusion state, and the first related VSS or storage event. Preserve identifiers needed to distinguish the affected devices while applying the organization’s normal redaction rules to customer-specific labels and paths.
Official Microsoft references
- Microsoft: IVssBackupComponents::GetWriterStatus
- Microsoft: determining VSS writer status
- Microsoft: VSS writer errors and vetoes
- Microsoft: VSS writers and their lifecycle
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