Hyper-v failed to open attachment C:\clusterstorage\volume

I recently installed a 2 node Hyper-V cluster soon to be a 3 node and all was working really well until I added a DPM 2010 Agent.When I was trying to do a live migration it would move 100% but fail to start. So if I shutdown the vm and move to another host and try and start it. It still wont start!!!!! :(

It was also affecting SCVMM , I could not push templates to my cluster.

I was starting to panic at this stage and was thinking I needed to rebuild my cluster, but the fix was really simple and required a few steps.

1) Start Registry Editor.
2) Visit the following registry key: “HKLM\SYSTEM\CurrentControlSet\Services\FsDepends”
3) Under the “FsDepends” key, change REG_DWORD value “Start” from “3” to “0”
4) Restart the computer

Another culprit was SOPHOS, I excluded cluster.exe , c:\clusterstorage and it still would fail. So I also excluded the volumes C:\Clusterstorage\volume1 , C:\Clusterstorage\volume2 etc.. and it all worked fine.

Also to remove any ISO images attached to any VM , Like exchange 2010SP1 iso, after the iso has been removed , go into cluster manager , right click on the virtual machine, click on more actions and refresh virtual machine configuration.

My live migration is working perfectly again.