Running ESXi 5.1.0 with local storage and had some VMs crash. Found one of the Datastores was missing. Rebooted ESXi and the Datastore is still missing and the VMs show up as "Unknown (inaccessible)" etc.
If I try and Add Storage, it sees a Local Disk but says the Partition Format is Unknown and the hard disk is blank.
How can I troubleshoot this?