Here’s one for you.
A Server that is IN a Cluster with Some Hyper-V resources Clustered and some not. The Clustered ones are backing up ok but the non Clustered ones?
You may find a couple of things to look out for. The Mysterious ID38 error when enumerating a NON Clustered Partition. It could well be that the machines in question that will not backup are trying to do a “Backup Using Saved State”.
This type of backup actually does a quick save of the state of the machine and grabs that directly from physical drive.
But in the Case of a Clustered server and DPM, if you encounter the mysterious ID 38 error (Can’t enumerate the resource) when trying to work with the drive that HAS the VHD files you will fail.
The trick is to identify the “WHY”
If you find the resources that are not backing up are using “Backup Using Saved State” you should refer to this Article on Technet to identify the “Why”
In my case, I had some test machines that had Dynamic drives which had to be switched back to “Basic”.
“But you can’t switch Dynamic back to Basic, that’s Madness!”
Well it DOES depend on the Dynamic Drive. If your Dynamic drive is a simple partition that got accidentally created as Dynamic or part of a “Software Mirror”…. Yes you can.
With a little time, you can undo that Dynamic Drive within the virtual machine and have a happier backup