I have two hosts in a Win 2008 R2 Hyper-V cluster. I moved my VMs to one host while I installed Windows updates on the other host. During the updates it also tried to install a Dell System Device Manager update. This update failed. After the updates I was not able to migrate VMs to the updated host. I've since backed out the Windows updates and updated the hardware drives on the Dell PE R610. If I go into Device Manager I see the vhdparser driver has an alert next to it.
I also see that most of my volumes listed in the Cluster Management Console are redirected. (all volumes are on the working Host)