ERROR_VHD_FORMAT_UNKNOWN 0xC03A0004

Hex 0xC03A0004 · Decimal -1069940732 · Type NTSTATUS

WINDOWS

The system does not recognize the file format of this virtual hard disk.

Windows troubleshooting diagram: Device Manager warning and a system file scan
Windows errors: check drivers, system files and Event Viewer, in that order.

What it means

ERROR_VHD_FORMAT_UNKNOWN is a Windows error code (NTSTATUS 0xC03A0004) reported by Windows. Its official message is: “The system does not recognize the file format of this virtual hard disk.”

How to fix ERROR_VHD_FORMAT_UNKNOWN

  1. Reboot once — many one-off system codes disappear with a clean restart
  2. Repair system files: 'sfc /scannow' then 'DISM /Online /Cleanup-Image /RestoreHealth'
  3. Find the source in Event Viewer → System: filter for this exact code and open its provider link

Related errors

ERROR_VHD_FORMAT_UNSUPPORTED_VERSIONERROR_VHD_DRIVE_FOOTER_CORRUPTERROR_VHD_DRIVE_FOOTER_CHECKSUM_MISMATCHERROR_VHD_SPARSE_HEADER_CHECKSUM_MISMATCHSTATUS_VHD_FORMAT_UNKNOWNSTATUS_VHD_DRIVE_FOOTER_CORRUPTSTATUS_VHD_FORMAT_UNSUPPORTED_VERSION

Source: Microsoft WinError.h

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