What does HRESULT 0x80820001 (ERROR_VOLSNAP_BOOTFILE_NOT_VALID) mean?

ERROR_VOLSNAP_BOOTFILE_NOT_VALID

Read the code at the owning storage layer: volsnap bootfile not valid

Windows returns ERROR_VOLSNAP_BOOTFILE_NOT_VALID, value 0x80820001, at the volsnap boundary. It means that the persistent-snapshot boot support file cannot hold the metadata needed to activate all configured snapshots during volume arrival. Preserve the exact handle and generation of persistent Volsnap activation metadata used while the volume comes online before any rescan changes the evidence.

Persistent shadow copies must survive volume dismount and later activation. Volsnap therefore needs durable activation metadata and enough time to enumerate and bring the stored snapshot state online before the mount sequence proceeds.

Keep the first result attached to its request parameters and object instance. Cleanup failures or a later drive-letter change are secondary evidence, not replacements for the original failure.

Build a trustworthy incident record

When it is followed by a secondary cleanup failure, store both codes with timestamps and retain this one as the initiating result.

Controlled comparison

1. Create a nonproduction case that preserves the same geometry and ownership model.
2. Collect volume GUID, persistent snapshot IDs, boot-support file path and size, volume-online timestamps, Volsnap/VSS events and storage latency during activation before invoking the first mutating API.
3. Change one condition only: create a controlled persistent snapshot on a test volume, reboot or cycle the volume online, and compare activation with a right-sized support file and low I/O load.
4. Re-enumerate after the transition and confirm this result is not reproduced by a stale handle from the old generation.

The distinction from ERROR_VOLSNAP_ACTIVATION_TIMEOUT is operational. The persistent-snapshot boot support file cannot hold the metadata needed to activate all configured snapshots during volume arrival; log the neighboring code separately so capability, identity and state are not conflated.

Mechanism-specific note

Persistent snapshots require activation metadata available early in the volume-online path. Record support-file size, number of snapshots and expected metadata demand. Resize or recreate the support mechanism through supported snapshot management; replacing the file blindly can orphan snapshots whose identifiers still exist.

Completion criteria

Preserve Volsnap and VSS evidence, correct the support-file capacity or activation bottleneck, and verify persistent snapshots across a complete volume-online cycle. Apply the change through the supported storage API, then close and reacquire affected objects before retrying.

• the first retry uses newly enumerated identifiers rather than cached handles.
• The durable metadata or provider state agrees with the success returned after it.
• A second run after close/reopen does not recreate the rejected condition.
• the nearby ERROR_VOLSNAP_ACTIVATION_TIMEOUT path remains separately testable and separately logged.

Technical references

• Microsoft: Volume Shadow Copy Service — primary API or object-model reference.
• Microsoft Open Specifications: VSS snapshot attributes — use this source to verify volsnap state and parameters.
• Microsoft: VSS backup components — documents the supported management path relevant to this HRESULT.
• Microsoft: COM error codes for VOLSNAP — defines the volsnap objects used to interpret it.