Today I came across a HyperV VM where new snapshots were not being shown in SCVMM. I then checked the HyperV console which showed all the new snapshots, but there was one in the chain that had the text "- backup -" in the checkpoint name, which could not be deleted from the HyperV GUI either (the delete checkpoint option was not in the menu).
The fix was to use powershell on the HyperV host to list the checkpoints for the affected VMs, and the undeletable checkpoint was listed as a "Recovery" checkpoint. These are created by backups, so before deleting you need to be sure that they are not being actively used by a backup process, but you can follow the powershell steps shown below:
The steps are to list all snapshots for the affected VM, then pipe the Recovery snapshot to the Remove-VMSnapshot command.
PS C:\Windows\system32> Get-VMSnapshot -VMName _VMName_ VMName Name SnapshotType CreationTime ParentSnapshotName ------ ---- ------------ ------------ ------------------ _VMName_ Checkpoint 1 Name Standard 4/04/2017 1:45:54 PM _VMName_ Checkpoint 2 Name Standard 4/04/2017 1:45:55 PM Checkpoint 1 Name _VMName_ Checkpoint 3 Name Recovery 4/04/2017 1:45:55 PM Checkpoint 2 Name _VMName_ Checkpoint 4 Name Standard 23/05/2017 4:24:18 PM Checkpoint 3 Name _VMName_ Checkpoint 5 Name Standard 23/05/2017 4:25:59 PM Checkpoint 4 Name _VMName_ Checkpoint 6 Name Standard 23/05/2017 8:32:08 PM Checkpoint 5 Name _VMName_ Checkpoint 7 Name Standard 23/05/2017 8:33:51 PM Checkpoint 6 Name _VMName_ Checkpoint 8 Name Standard 23/05/2017 8:43:37 PM Checkpoint 7 Name _VMName_ Checkpoint 9 Name Standard 23/05/2017 9:38:07 PM Checkpoint 8 Name _VMName_ Checkpoint 10 Name Standard 23/05/2017 9:45:40 PM Checkpoint 9 Name PS C:\Windows\system32> $s=Get-VMSnapshot -VMName _VMName_ PS C:\Windows\system32> $s[2] VMName Name SnapshotType CreationTime ParentSnapshotName ------ ---- ------------ ------------ ------------------ _VMName_ Checkpoint 3 Name Recovery 4/04/2017 1:45:55 PM Checkpoint 2 Name PS C:\Windows\system32> $s[2] | Remove-VMSnapshot