Server Version#: 1.42.2.10156
When I go in the advanced options of a library and change the agent to TMDB, I have a message requiring that I upgrade the library so I do. Plex goes through the library, there’s no error message or anything, and when I go back and check the agent is back to Plex Agent. I change it again and it asks to upgrade and it repeats the same thing over and over.
I’m really not sure what I’m doing wrong here 
Don’t do that. The dedicated TMDB agent (and the TVDB agent too) is deprecated.
Just leave the agent as it is.
If this is a TV series library, change only the Episode Ordering on the Advanced tab to “TheMovieDB (Aired)” if it’s set to something else.
If you are fighting with matching issues, stick to the naming guides more closely.
In difficult cases, add a matching hint to the folder names, and then perform the Plex Dance if necessary.
Plex won’t match with some movies/series that’s on IMDB, even with the formatting of the name right. I tried searching with the IMDB ID in the title but it doesn’t work either.
They’re TV mini-series but all the episodes are one long video so it watches like a movie. I tried putting it in the movie category and it won’t match, I tried putting it in a folder with the name of the series and put it in the TV series category and it just won’t see it at all and the library stays empty. I guess matching won’t be possible then?
Don’t look up series on IMDb.
Always go to TheMovieDB.org first, then to TheTVDB.com second, to see if they are there.
Generally you won’t be able to match a “mini series” in a movie-type library in Plex.
Always add these to a tv show library.
