Hi!
Jellyfin (that awesome self-hosted media center, btw) has a peculiar behaviour regarding updating / deleting files from the filesystem (not from the Jellyfin UI) - it ignores such events. And that can mess up your libraries being scanned.
For example, you've added a folder with a TV show to a freshly created library. Then you've scanned it and everything worked as intended - the videos are there and playable. But then, after finishing the series from that folder you went and deleted the directory from the filesystem. Well, that's a mistake - now Jellyfin still has the references to those files, but they are absent in the filesystem. This breaks the library scanning and Jellyfin won't be able to recognize new files when you add them. Moreover, the library recreation doesn't work either - seems like it's just restored from the DB (it is, when you use the same names)
So, we'll need to remove those dangling references and rescan the library once again. General steps are:
Delete the troublesome folder from Jellyfin UI, if you have it there.
