This is the most common scenario. An administrator accidentally deletes the VMFS partition table in the vSphere client or uses fdisk on the ESXi shell to wipe the volume. The data is still on the disk platters, but the map to find it (the partition table and VMFS header) is gone.

When the volume is unmountable or files were accidentally deleted, specialized software is required because standard OSs like Windows cannot read VMFS partitions. VMFS Recovery. Basics, methodology and possible approaches

vmfs-tools is excellent for VMFS 3 and VMFS 5, but it has limited support for VMFS 6. If you are running a modern environment (vSphere 6.5+), you likely need a different approach.

The list returned the device: naa.6782a4b2c91d0001 . Capacity: 12TB. Partition table: . His stomach dropped. A storage engineer on the call confirmed the SAN had lost a controller for 47 seconds during a firmware update. A cascading write error. The partition table, the file system’s map of the world, had been shredded.

If you see the volume, use esxcfg-volume -m [UUID] to mount it persistently.

Accidental formatting or "initializing" by a non-ESXi operating system (like Windows or Linux) can overwrite critical VMFS "Lock" and "Heartbeat" regions.

The tool spat out a wall of hexadecimal. For a full minute, nothing but scrolling symbols. Then, a line of hope: