Virtual Machines Manually Migrated from an ESX Server 2.x Host to an ESX Server 3.x Host Subsequently Might Not Power On
Details
When a virtual machine residing on a shared VMFS-2 volume is migrated from an ESX Server 2.x host to an ESX Server 3.x host using the Migrate Virtual Machine wizard, if the "keep virtual machine files and disks in their current location" option is selected, the virtual machine will migrate but not power on subsequently.
Solution
When performing this type of migration, select a VMFS-3 volume as the destination datastore.