The following command returns the list of snapshots for the VM and its type:
Generally, DPM requests Hyper-V to create a checkpoint for the virtual machine as part of the VM backup process. After DPM completes the backup, it sends a backup complete notice, and then Hyper-V merges the checkpoint back into the primary .vhd file and deletes the .avhd file.
What causes broken checkpoints?
There is a known issue in which Windows Server leaves a virtual machine in a locked or backup state even after backup is complete. To resolve this issue, apply the hotfix that's described in Hyper-V virtual machine backup leaves the VM in a locked state.
However, even after you do this, the broken recovery checkpoints remain.
This resource also suggests that a better solution (if you have 2008 R2 or later) is to create a snapshot of the VM. Then, select that snapshot and export it. This creates a copy of your VM in a single VHD file. You can then remove the old VM and import the new one.
Article ID: 3059372 - Last Review: 29 Apr 2015 - Revision: 1