I have all my music very well set up and organised. However after 2 years of not updating it, I added some new stuff and noticed latest version of Plex is no longer picking up folder.jpg in the Artist folder as a thumbnail. However folder.jpg in the Albums subfolders is still being picked up fine though? Nothing has changed this end, and it worked fine a year ago. I am using latest (non beta) server release.
eg: every artist will contain files like this:-
m:\media\music\alt\Arcade Fire\folder.jpg (no longer loads)
m:\media\music\alt\Arcade Fire\The Suburbs\folder.jpg (still loads)
m:\media\music\alt\Arcade Fire\The Suburbs\1.01. Arcade Fire - The Suburbs.flac
It used to work 2 years ago as my music library still has them all.
What I am doing is, I cloned one of my music libraries to rename without disc.track. prefix :-
m:\media\music\alt\Arcade Fire\The Suburbs\Arcade Fire - The Suburbs.flac
The reason being I also have a music video which needs to be named same as track to match up but then in Artist extras all videos have this disc.track. prefix which is ugly.
If that made a difference, it means you have your library still on the old and deprecated Python metadata agent.
This one will be removed from Plex eventually.
Kodi, Emby, Jellyfin all support nfo. You get your metadata once then it’s there forever + easily tweaked/fixed and created for personal media that won’t exist via scrapers. Had Plex implemented this approach a decade ago it would have saved endless problems. Features constantly get added then abandoned while the core functionality remains slow and fragile. Oh well…