Changing the User Plex Runs as on Ubuntu 15.10

Changing the user Plex runs as is quite simple.

First stop Plex:

service plexmediaserver stop

Edit the service file ‘/etc/systemd/system/plexmediaserver.service’and change the ‘User’ and ‘Group’ values to your new user and group:

User=newuser
Group=newuser

Edit the defaults file: ‘/etc/default/plexmediaserver’ and change the ‘PLEX_MEDIA_SERVER_USER’ option:

PLEX_MEDIA_SERVER_USER=newuser

Add your user to the Plex group:

useradd -G plex newuser

Allow the plexmediaserver directory to be writable by groups:

chmod 771 -R /var/lib/plexmediaserver/

Thats it! Start the Plex service again with:

service plexmediaserver stop

And plex should be ready to go with the new user.

Note:
If you change the user Plex runs as you might need to move the Application Support directory to not lose your media library.