Plex always needs permission to see your files. It has no administrative privileges as of version 1.15.4.994
DSM 7 changed the username and how it’s defined
– PlexMediaServer is now the “System Internal User” username. This is a “Service” account name. It’s not a Login-capable user.
– Username “Plex” was abandoned in DSM 7 due to how Synology packaging changed.
All the changes are documented here:
Because the entire packaging system changed, we had to rewrite the entire Synology package installer and control mechanisms from scratch.
In doing so, we added the packaging menus (as you install) with reporting windows giving you the results upon completion of the installation.
If you look at that final popup, it tells you exactly how to grant permission for System Internal User PlexMediaServer to read your media again in DSM 7.
Since it appears you missed it, I’ve placed the procedure (with screenshots) here:
