Microsoft made available another update of a fix which improves cluster resiliency. I lost count now but believe this is the fourth try of Microsoft to fix a number of issues which are storage related.

One of the readers of my blog applied this latest hotfix KB2848344 and wrote me:

I’ve applied this fix on 2 nodes in a two node HV failover cluster. (LAB based on iSCSI shared storage)
DPM2012SP1 with latest rollups is still not able to backup a single VM on this cluster.
DPM encountered a retryable VSS error…

KB2848344 is titled  Update improves cluster resiliency in Windows Server 2012 and was released June 13, 2013.

I blogged about previous storage issue and the Microsoft attempts to solve this here:
Microsoft releases 2nd bug fix to fix issues on CSV backup of Windows Server 2012 Hyper-V
Storage issues on Windows Server 2012 Hyper-V. Microsoft struggling to fix!
and here
Important update that improves cluster resiliency in Windows Server 2012 is available

--> Please see the rest on the blog :