Marcus opened Disk Management (diskmgmt.msc). He clicked Action > Attach VHD . The dialog hung for 45 seconds before spitting out: "Virtual Disk Manager: The virtual disk is corrupted or unreadable."

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: .

Mount-VHD -Path E:\VHDs\prod_db_backup_2024.vhd -NoDriveLetter Get-Disk | Where-Object OperationalStatus -eq "OK" A new disk appeared: Disk 4 (Offline) . He brought it online, assigned a drive letter Z: , and held his breath.

He ran:

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.

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.

Next, he tried -> Edit Disk . The wizard froze at 12% while attempting to compact the drive. No dice.