I had an issue where a change caused my Exchange cluster to loose all it’s SAN connected disks and it kept failing over. When opening Cluster Administrator I received an error stating a duplicate MSDTC resource can’t run and within the cluster admin the MSDTC resource did not want to start. I then took all resources offline andshut down all the cluster nodes. Started up Node 1, then Node 2 and lastly node 3. I started all resources on the first node including the MSDTC resource. Then started resources on Node2 and all was fine again