So I have 2 ESX 4.0 boxes and I'm migrating all the machines to a new ESXi 5.5 box. The 5.5 box can't see one of the iSCSI targets that the other 2 can. The only way I can add it is by using the vSphere client application to add the storage, where I can see it, however I'm unable to add it without formatting it. Obviously this is not desirable. Why is it this storage is unable to be used without formatting? All the iSCSI targets are from the same machine, they were all created the same way as far as I can tell, so why is this one unable to be added without a format?