It is an all or nothing kind of thing.
- All episodes must be named & organized correctly, not just one or two files.
- Local Media Assets must be at the bottom of the list to protect against poor metadata.
- You have to Plex Dance the entire show, not just a few episodes.
When adding the show back to your server, you can add just one or two episodes to start. Plex will have to scan fewer files, download less metadata, etc. Once you have things working correctly, you can modify the remaining episodes and add them to the server.
Same here.
For Mac users, Subler, https://subler.org/, is a good metadata editor for MP4/M4V files (also for muxing in subtitles & other tracks).
