External utilities (like a Windows/Linux OS) may accidentally re-initialize the LUN, overwriting the VMFS header.
If partition table lost, recreate first partition starting at sector 128 (typical) or 2048 with VMFS type: recover vmfs datastore esxi 5
Sometimes the partition table is corrupt but VMFS data remains. FB 0 First
partedUtil set /dev/disks/naa.YOUR_DISK_ID 1 128 <end_sector> FB 0 recover vmfs datastore esxi 5
First, SSH into the ESXi host as root .