First, make sure your library and metadata agents are configured to prefer local metadata.
Second, the newer scanner is more accurate than the old one, but, it’s also pickier about
- a) correct embedded tags, and
- b) album titles matching folder names (this one makes no sense to me, but that’s the way it is)
For a box set, these things need to be true:
- The Album tag must be identical in all tracks
- The Album Artist tag must be identical in all tracks
- The disc number tag must be properly populated (see screenshot in the thread linked above)
- Do not use something like “1 of 10” or “1/10” in the Track Number field.
Having the year in your filenames might be causing a problem. You’re better off removing it from the filename and making sure the embedded tag is correct. My filenames are strictly “|Track| - |Title|.ext” (e.g. “01 - Concerto In F major - I. Allegro.flac”)
If you have a 2 or 3-disc box set, try these tips with that set first, before tackling your big one(s).
You’re certainly not alone in frustration with Plex and classical music (and not just Plex, either). You might want to take a look at this feature request. It explains most of Plex’s shortcomings with regard to classical music:
