You have migrated your virtual machines to new storage but find that the summary tab of the virtual machines shows two datastores within the vSphere Web Client and vSphere Client. You have checked the datastore and no data resides on the LUN.

Here are a couple of things you want to check,

1) The most obvious is to check whether there are ISO’s mounted to your servers

2) vSwap file. Does a vSwap file exist on the data store? browse the datastore and check if any vSwap files exist. If yes, a VMotion of the Virtual Machine migrates the vswap to the new location. If you’re moving VM’s to new storage, don’t forget to check your vSwap configuration, especially if you originally configured the vSwap location to reside on a different LUN. Ensure the vSwap file location has been reconfigured to point to new storage.

3) Check if any VMWare snapshots exist. If a VMWare snapshot was taken whilst an ISO was attached to the VM, this could be the issue. Remove the snapshot