@sha256 said:
We’re getting somewhere now. I took one test show with one season and 3 episodes in it, did the plex dance, and dropped the files into a new library. There, I was able to see and select many different episode thumbnails! Yay! (no season thumbnails but then I realized that, ugh, I had named the folder “Season 1” instead of “Season 01” - I can’t believe that actually makes a difference, and it didn’t use to when I first started using plex in 2014 but…oh well)
That is an interesting twist in this mystery. I always use 01 myself, but I do have plenty of previously matched 1s that are working and always assumed 1s would work as well as 01s - maybe not - but here’s what I think is happening:
You are leaving out one or more of The Plex Dance® steps and that bogus bundle for that ‘old show’ still remains. When you create a new library and a new and proper structure Plex thinks it’s a new show and writes a good bundle for it. Drop it back in that old library and the old bogus bundle kicks in.
That’s 100% guesswork on my part, but it sounds good. 
So then I tried doing the plex dance on a different TV show, except this time after renaming everything - perfectly in compliance this time, down to the 01 instead of 1 - I put the show back in its original TV show library.
The problem immediately reocurred - I can see different options for Series posters and backdrops, but nothing shows up for Season posters and episode thumbnails. One thing of note - Plex seems to have “remembered” that I had already watched this test show. Every episode was marked as watched. Gah! I was under the impression that deleting the show from plex, deleting bundles and emptying trash would purge all that stuff from that library’s database. Is there ANY way to get an existing Plex library to forget all about a show, so I can re-add it with a fresh, compliant folder structure?
I’ve noticed that too. Plex keeps that watched status somewhere other than a bundle apparently, because I whack many bundles often and replace them with brand new ones and - yep - that watched status lingers on.
It’s easy enough to go to the front end of a show and mark them all as watched, or unwatched, so that little fly speck on the wall is no problem.
The 800LB Gorilla in the room is that you have discovered the wonders of compliance (FileBot is your friend) and your future life with Plex is going to go along more smoothly now that you have seen the light.
I think the most productive steps you could do are continue with a new library - or libraries. As you bring stuff into complete compliance whack their old versions (update library, clean bundles, empty trash) then drop perfectly named and structured stuff into the new Library - or Libraries. Eventually you’ll get where you needed to be all along.
The trick to this whole thing is to have compliant material BEFORE it hits the libraries and FileBot will absolutely make that happen because FileBot goes to the database, gets the exact names, knows the structures (if you don’t - you should let it do ALL the work) and names your stuff perfectly. There is no guesswork. When you drop it in a library it matches the first time every time and you can concentrate on some other dramatic event - not that one.
