I recently upgraded two test hosts to vSphere. Both hosts were placed in a non EVC enabled cluster. After upgrading the vmware tools and the virtual hardware version from version 4 to 7 I noticed I was no longer able to vMotion some virtual machines. Turns out that during the virtual hardware upgrade there may be CPU masks added to the virtual machine. Adding the two hosts and all of the VMs to an EVC enabled cluster fixed the issue, so I wasn’t too worried about it. Today I read KB1011294…
