It sounds like the permissions on the “Plex” shared folder were manually set at some point and when upgrading to DSM 7, the new installer (because it isn’t administrator anymore) couldn’t read the shared folder.
The remedy for this, assuming your DSM 6 -based server is fully intact in the “Plex” shared folder, is:
- Uninstall the existing DSM 7 package with the ERASE option.
- Control Panel - Shared Folders - EDIT the “Plex” shared folder - Permissions tab
Now follow “Scenario 2” as shown here.
Your goal is to update the permissions for all folders and files in the “Plex” share and grant “PlexMediaServer” (the new service username) Full Control of all files.
- This will likely take some time to complete.
- When complete, you may reinstall PMS. The installer will automatically start processing (migrating) the DSM 6 Plex installation to DSM 7.
Be patient with this … It will take 2-3 minutes for each 1000 media items you have index by PMS
