The /media directory, is a special case on any system which has the Gnome desktop.
If you look /media/pi/MYSTERY permissions are probably set for you exclusively.
When running Gnome, and here’s what gets everyone, Nautilus mounts the USB EXCLUSIVE to your username. User plex can’t read it in spite of the permissions.
You’ll see it fine – Plex will be excluded.
Therefore, I suggest trying to mount it with this method:
You’re looking to use the UUID= method to mount the USB drive in a location which is not under /media.
Any non-conflicting directory, outside your home directory, will do.
Please review that and see if it might help this case. I know the Pi itself is a special case.
