I've run into this problem a few times and I am trying to understand what I am doing wrong--
Let's say I have a VM called 'VM1' and it's running on a Hyper-V host called "HOST1".
I then add a new physical volume to the host and mount it at C:\SAN\VMDATA. I then create a .vhdx in this location and attach it to 'VM1'.
I update the inventory and make sure the new storage is recognized but whenever the backup runs, it fails . If I logon to "HOST1" and check the event log the error message is "Could not create backup checkpoint for virtual machine 'VM1': General access denied error (0x80070005)." The only way I have got it to work is if I change the "Checkpoint File Location" in Hyper-V manager to the new .vhdx storage location.
Is there a better way to be handling this or is there a step that I am missing?