Vhd - Repair Corrupt

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."

The tool had detected that the dynamic VHD header had a checksum mismatch—likely from an unclean Hyper-V host shutdown. VHDTool recalculated the checksum and zeroed out the corrupted BAT entry that pointed to a non-existent sector. repair corrupt vhd

Then he ran:

vhdtool.exe /repair "E:\VHDs\prod_db_backup_2024.vhd" The output was promising: [INFO] Footer found at offset 4294967296. [INFO] Header checksum invalid. Recalculating... [INFO] Rebuilding BAT. 1 invalid block entry removed. [SUCCESS] VHD repaired. Marcus opened Disk Management (diskmgmt

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. VHDTool recalculated the checksum and zeroed out the

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.