I sometimes re-rip a movie to get a better copy in my database. Often my early rips were not particularly good or the movie is from one I inherited from my uncle and he was not very good at making the best rips and/or the tools available were not as good as the ones used today.
Usually when I do this I verify the new rip and then replace the old file with the new one and, if the extension is different, I delete the old file manually.
Once in a while I fail to delete the old file and I end up with two copies of the movie which Plex shows as a single file with a 2 in the corner. This is as expected and I, from time to time, use the duplicates filter to see where I have two files and then I delete the older one.
Recently I re-ripped “A Streetcar Named Desire (1951)” and did not correctly delete the old rip. The two separate entries were named “A Streetcar Named Desire (1951).mkv” and “A Streetcar Named Desire (1951).mp4” with the mp4 being the older and smaller and poorer one.
For some reason Plex ended up with two separate but identical entries for the movie. Everything I could see in Plex was exactly the same poster, description, year and all other data I could see were exactly the same and the entries were next to each other in the database.
Plex should have detected this situation as a duplicate and merged the two but it did not.
Unfortunately I have already fixed the problem so no logs or other info are available. I am posting this here simply to ask if anyone has any ideas as to why this occurred as it has never happened on any other file before.
BTW: I only noticed it today but the re-rip and addition took place about two weeks ago so it is not a case of Plex just not getting around to it.
My crystal ball says: 
Back when the old file version was added, you used a different metadata agent.
Later, you changed the default metadata agent of the movie library.
Then you added the new version which was of course ‘matched’ with the new metadata agent.
Result: the two versions have different guid='s.
(You can see these in the Plex XML info )
With different guid’s, Plex has no way to recognise they’re the same movie.
@OttoKerner said:
My crystal ball says: 
Back when the old file version was added, you used a different metadata agent.
Later, you changed the default metadata agent of the movie library.
Then you added the new version which was of course ‘matched’ with the new metadata agent.
Result: the two versions have different guid='s.
(You can see these in the Plex XML info )
With different guid’s, Plex has no way to recognise they’re the same movie.
That is a good guess I think. I do not think “Plex Movie” was an option back when “A Streetcar Named Desire (1951)” was first added.
But I still wonder why this is the first problem like this I have hit as there have been a number of rerips of movies added from that same time frame. But it really does not matter too much as it is fixed and I have more pressing problems, like what to fix for supper, than this one. I am just a bit curious. “Curiouser and curiouser!” Cried Alice.
@Elijah_Baley said:
That is a good guess I think. I do not think “Plex Movie” was an option back when “A Streetcar Named Desire (1951)” was first added.
But I still wonder why this is the first problem like this I have hit as there have been a number of rerips of movies added from that same time frame.
‘Plex Movie’ uses the same guid which ‘Freebase’ used previously: imdb
They’re kinda closely related.
