What does HRESULT 0xC038004F (ERROR_VOLMGR_BAD_BOOT_DISK) mean?

ERROR_VOLMGR_BAD_BOOT_DISK

What this result says about the disk model: volmgr bad boot disk

The practical meaning of ERROR_VOLMGR_BAD_BOOT_DISK (0xC038004F) is tied to logical volume geometry and the disk extents that realize it: the disk that carries boot-critical volume metadata is reporting failures that make the planned layout change unsafe. The result does not, by itself, prove file-system corruption or physical-media failure.

Capture the exact object instance

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

Prove the condition in a test volume

1. Before changing state, freeze the failing generation and save pack and volume IDs, input structure version and sizes, transaction ID, disk-layout snapshot before the call and the first kernel storage event.
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.

A useful diagnostic fork is ERROR_VOLMGR_UNEXPECTED_DISK_LAYOUT_CHANGE versus this result. This code concerns the disk that carries boot-critical volume metadata is reporting failures that make the planned layout change unsafe; the alternate code should remain observable after the fix, proving the application did not suppress the entire subsystem.

Mechanism-specific note

Boot-critical placement raises the safety bar because losing the disk can affect both startup and the dynamic-disk configuration. Preserve storage health, path redundancy and recent I/O errors. Move or repair boot dependencies through supported boot and storage tooling; a successful metadata write alone does not prove the system remains bootable.

Safe recovery path

Restore access to the identified disk or extent and confirm its identity and health; do not substitute a different disk merely because its size matches. 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 it.
• 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 — 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.