Hyper-V backups failing with " Error exposing VSS snapshot " (4044071)

HyperV backups failing with " Error exposing VSS snapshot "

The reason the snapshots can not be exposed is because there may be already older shadows listed that Hyper-V was not able to clean up from failed previous backups.
If a backup job is aborted or fails while a VSS snapshot is being used, it is possible that Hyper-V Plugin will not be able to clean up the VSS snapshot. If this happens,
 

You will need to use a tool such as Microsoft's CLI diskshadow.exe can be used to remove the snapshot. After diskshadow is run from the command line, execute the following
commands at the DISKSHADOW> prompt to find and remove the orphaned shadow copy. Enter:

list shadows all

The preceding command will list the current shadow copies. Look through the list of shadow copies noting the Exposed Locally as field. Find the field with the
exposed directory name matching the VM name used during the aborted or failed job. Using the Shadow copy ID field from that entry, run the following command:

delete shadows ID <Shadow copy ID from aborted or failed job>