Hi All,

Recently had an issue at a customer whereby a two node windows server 2012 file server cluster would fail to communicate with the passive node when that node was moved to another hyper-v host in the hyper-v cluster.

When both virtual machines were on the same node, they communicated fine.

After copious amounts of troubleshooting this issue turned out to be a new Windows Server 2012 feature; the failover clustering filter driver that gets added to the virtual NIC that is bound to a hyper-v switch.

Full details and fix here :)