If a LUN's UUID changes, ESXi may see it as a snapshot and refuse to mount it automatically to prevent data collision.
: Use esxcfg-volume -m "Label/UUID" (unmounts after reboot). recover vmfs datastore esxi 6
If you have recent backups, restore to a new datastore—that’s always the fastest and safest recovery. But when backups are absent, the steps above give you a fighting chance. If a LUN's UUID changes, ESXi may see
To mount it without changing the UUID (useful for testing): esxcfg-volume -m "DatastoreName" Use code with caution. If a LUN's UUID changes