DPM 2012 R2 (ID 104 Details: Internal error code: 0x809909FF)

Question

We are running DPM 2012 R2 on Windows Server 2012 R2
We have a Protection Group:Servers (9 members) where 5 servers always give the same error message, when we try to run a synchronization job with consistency check. With other 4 server everything is fine. (All 9 servers: Windows Server 2012 R2)
All servers have "Windows Server Backup" feature installed
Error message:
The replica of Microsoft Hyper-V \Online\S022 Reports on S022 Reports.SynCrust.********.eu is inconsistent with the protected data source. All protection activities for data source will fail until the replica is synchronized with consistency check. You can
recover data from existing recovery points, but new recovery points cannot be created until the replica is consistent.
For SharePoint farm, recovery points will continue getting created with the databases that are consistent. To backup inconsistent databases, run a consistency check on the farm. (ID 3106)
Any help would be appreciated

Answer 1

Just wanted to add some further details to this thread...
As suggested in
this article, Windows Server Backup has been installed on all 3 cluster nodes. I have also tried disabling/enabling the WinRE agent, as it suggests, with no effect.
The Virtual Machine I am trying to back up is running Windows Server 2008 R2 with the latest updates, and has integration services version 6.3.9600 installed.
Additional searching led me to
this article, which states "DPM works seamlessly with Hyper-V VSS writer to ensure that consistent versions of virtual machines are captured and protected without affecting virtual machine access." It doesn't clarify if this is the method used
when backing up VMs stored in a CSV, however. Regardless, the Hyper-V VSS writer is not listed when issuing
vssadmin list providers
I went through the steps outlined in
this article to install the writer, but even after following said steps, the writer still does not appear as registered on the Windows Server 2012 R2 cluster node via the above command.
I should also mention that
this prereqs article mentions that the Hyper-V role should be installed on the DPM server. The hardware I'm using has an old AMD Sempron 3400+ CPU, so I'm unable to install this role on the DPM. The article states "DPM protects Hyper-V virtual
machines even without the role, but you cannot perform item-level recovery (ILR) unless the role is installed.", so it's doubtful that lack of the role would cause this issue; MindaugasKa, is the Hyper-V role installed on your DPM?
Despite the effort of upgrading my storage server to Windows Storage Server Standard 2012 R2, my cluster nodes to Windows Server 2012 R2 Datacenter, and my DPM to 2012 R2, the
nightmare continues...