Then he ran:
He ran:
The sector size was misaligned. The VHD's internal "footer" (the last 512 bytes of the file) was intact—he confirmed that with a hex dump—but the BAT (Block Allocation Table) had a phantom block pointing to a sector that didn't exist. repair corrupt vhd
Marcus knew a trick: mount the VHD as a raw disk using a loopback driver. He used OSFMount from PassMark. He mounted the VHD as a read-only raw drive letter Y: . Then he ran: He ran: The sector size was misaligned
His hands went cold. That 4TB fixed-size VHD wasn't just any file. It was the last known good snapshot of a legacy SQL server for a municipal transit authority. The physical server had died three hours ago. The differential backups had been silently failing for six months. This VHD was the only lifeline. He used OSFMount from PassMark
Mount-VHD -Path E:\VHDs\prod_db_backup_2024.vhd -ReadOnly The error was cryptic: The VHD is corrupted. The block allocation table is inconsistent.