What does HRESULT 0xC038004E (ERROR_VOLMGR_DIFFERENT_SECTOR_SIZE) mean?

ERROR_VOLMGR_DIFFERENT_SECTOR_SIZE

Read the code at the owning storage layer: volmgr different sector size

Windows returns ERROR_VOLMGR_DIFFERENT_SECTOR_SIZE, value 0xC038004E, at the volmgr boundary. It means that the candidate disks expose different logical sector sizes and cannot share the requested volume geometry. Preserve the exact handle and generation of logical volume geometry and the disk extents that realize it before any rescan changes the evidence.

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

Do not overwrite this result with a close, detach or rollback error. Preserve the causal order so the original storage contract remains visible.

Controlled comparison

1. serialize the failing request and the enumeration from which its identifiers came.
2. Preserve volume ID, requested length, sector sizes, extent table, plex/member counts, disk health and the exact VM_VOLUME_LAYOUT buffer while every handle is still valid.
3. Close and reacquire the relevant objects, then run once more to test lifecycle correctness after this result.

Use ERROR_VOLMGR_UNEXPECTED_DISK_LAYOUT_CHANGE as the nearest comparison. This result is specific to the candidate disks expose different logical sector sizes and cannot share the requested volume geometry; the neighboring result belongs to another validation or lifecycle branch. Keeping both names prevents a generic storage label from hiding the actual owner.

Mechanism-specific note

Record logical and physical sector sizes for every layer: image format, host file system and physical disk. Alignment must be checked with integer arithmetic before truncation. Copying an image to a different device can change the host geometry even when the image bytes and virtual capacity remain identical.

Completion criteria

Refresh the disk layout, serialize the change as one volume-manager transaction and reject any external partition mutation until commit or rollback completes. Keep the correction scoped to the owning object and avoid rewriting adjacent metadata merely to make the call return success.

• 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_VOLMGR_UNEXPECTED_DISK_LAYOUT_CHANGE path remains separately testable and separately logged.

A reboot, blanket disk conversion or deletion of storage metadata is not a justified first response to this result; such a change alters multiple invariants and can erase the evidence needed to identify the defect.

Technical references

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