Unfortunately the LUNS are not shared or I would have done that already. We are going to shared storage, but don't have Vcenter on it yet.
Normally if the problem was the CPU mask it would not even let you start the Vmotion. However it does. And it also failed with hosts in the same EVC cluster before we moved them all to 6.
I will try Grecos steps in a moment. Vcenter is a Windows 2012 R2 server.