DPM 2016 End User Recovery isn't working - DPM shares report "The device is not ready"

Hi all,

We're having issues getting End User Recovery working in DPM 2016 for our file servers.

• The "Previous Versions" tab reports "There are no previous versions available"
• The servers are backing up correctly, recovery points are being created and we can restore files using the DPM console
• DPM is correctly populating AD with the ms-srvShareMapping records

The problem seems to be that the shares on the primary DPM server have been created but report "The device is not ready" when trying to access them.  Looking at the paths that have been shared they all start with \\?\ ie "\\?\C:\Program Files\Microsoft System Center 2016\DPM\DPM\Volumes\Replica\7a26ba55-0a79-4359-b9d1-025166e8e833\8365be07-32e3-4a96-b576-d90db3765e95\Full\Shared"

The path works if you drop the \\?\ from it.

We are using Modern Backup Storage (which is awesome!!)

Has anyone come across this? Has anyone get End User Recovery working with DPM 2016?  Thanks!