What does HRESULT 0xC0380028 (ERROR_VOLMGR_MEMBER_REGENERATING) mean?

ERROR_VOLMGR_MEMBER_REGENERATING

Locate the rejected storage invariant: volmgr member regenerating

The practical meaning of ERROR_VOLMGR_MEMBER_REGENERATING (0xC0380028) is tied to dynamic-volume plex member descriptor and its backing extents: the member already has an active regeneration job and cannot accept another state-changing request. The result does not, by itself, prove file-system corruption or physical-media failure.

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.

Evidence to preserve before repair

Keep this HRESULT as the primary result if rollback or cleanup reports another code; those later values describe recovery, not the first rejected invariant.

One-variable reproduction

1. Capture the API parameters and object map that led to this result; do not begin with cleanup.
2. Build a passing control with the same disks or image copy and preserve pack ID, volume ID, plex index, member index, disk IDs, extent offsets, health state and regeneration percentage.
3. Run the narrow transition described here: start one rebuild, confirm its job identity and progress, issue the second request, then retry after the first job completes.
4. Compare resulting IDs, counts, health and ownership to prove the caller crossed the result invariant rather than suppressing it.

The distinction from ERROR_VOLMGR_MEMBER_IN_SYNC is operational. The member already has an active regeneration job and cannot accept another state-changing request; log the neighboring code separately so capability, identity and state are not conflated.

Mechanism-specific note

Regeneration has its own asynchronous job lifetime. Capture the job or task identity, source copy, target member, progress and last error. Starting a second job can compete for the same extents and obscures whether the first operation is progressing, paused or blocked on media I/O.

Repair without rewriting unrelated metadata

Wait for the owning job or transaction to reach a terminal state, then refresh all identifiers before issuing a single retry. After correcting it, reopen the pack, volume, tier, snapshot or virtual disk so no cached generation participates in the validation run.

• The original request now reaches success or a documented later status with the intended layout and access mode.
• A new enumeration reports internally consistent IDs, counts, geometry and ownership for the corrected object.
• The passing state survives the relevant lifecycle transition, such as reopen, remount, owner change or detach/attach.
• The application still distinguishes it from ERROR_VOLMGR_MEMBER_IN_SYNC and has no unbounded retry loop.

Technical references

• Microsoft: COM error codes for VOLMGR, VHD and SDIAG — use this source to verify volmgr state and parameters.
• Microsoft: Virtual Disk Service object model — documents the supported management path relevant to this HRESULT.
• Microsoft: Pack object — defines the volmgr objects used to interpret it.
• Microsoft: Virtual Disk Service common return codes — primary API or object-model reference.