What does HRESULT 0xC038003E (ERROR_VOLMGR_PLEX_TYPE_INVALID) mean?

ERROR_VOLMGR_PLEX_TYPE_INVALID

Interpret the state transition: volmgr plex type invalid

ERROR_VOLMGR_PLEX_TYPE_INVALID has unsigned value 0xC038003E. In the volmgr layer, the operation is rejected because the plex-type field does not describe a supported simple, spanned, striped, mirrored or RAID-5 organization. Diagnosis of this result should follow volume plex descriptor, layout type and regeneration state through one controlled state transition.

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.

Record geometry, identity and ownership

A management layer handling this result should report later recovery errors separately, because they answer a different question from the failed storage operation.

Separate validation from capability

1. Before changing state, freeze the failing generation and save volume ID, plex ordinal, plex type, member array, active/inactive state, health status and current regeneration job.
2. Exercise this exact comparison: serialize the exact VM_VOLUME_LAYOUT buffer, validate every count and Size field, and compare it with a layout produced by a known-good management API.
3. During the comparison, keep image bytes, unrelated disks, provider policy and cluster topology fixed.
4. After the test, record the next return value and the durable object state; crossing the boundary should expose a later result rather than silently retrying.

ERROR_VOLMGR_UNEXPECTED_DISK_LAYOUT_CHANGE describes a nearby but different storage condition; this result indicates that the plex-type field does not describe a supported simple, spanned, striped, mirrored or RAID-5 organization.

Mechanism-specific note

Plex type determines how extents are interpreted and which maintenance operations are meaningful. Log the raw type value and the member geometry used to infer it. Do not map an unknown value to “simple” as a fallback, because that can reinterpret striped or parity metadata as a linear extent list.

Verification after correction

Select an operation compatible with the actual plex type and keep at least one active data copy throughout detach, repair or regeneration. Keep the correction scoped to the owning object and avoid rewriting adjacent metadata merely to make the call return success.

• The controlled A/B case changes only the invariant that triggers this result.
• No unrelated disk, cluster owner, tier policy or virtual-disk backing file is altered to hide this result.
• Health, synchronization or job state reaches a terminal value consistent with the repaired operation.
• Telemetry includes both symbolic names when it or ERROR_VOLMGR_UNEXPECTED_DISK_LAYOUT_CHANGE occurs again.

Technical references

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