Added library causes various problems on various devices

I added a library of about 500 movies to my Plex Server running on Windows 10. Prior to adding this library everything ran fine on all devices. This library has been added to one Home user and not to another Home user.

  • Plex runs fine on iphone. Library movies play fine on iphone.
  • Plex runs fine on Chrome browser running on Plex server computer. Library movies play fine there.
  • Plex runs fine on Chrome browser on a different computer. Library shows a warning exclamation point and gives a “Not found” when clicked on.
  • Samsung Plex app starts fine. If I choose the user without the added library, Plex runs fine. If I choose the user with the added library, Plex shows an eternal spinner.
  • Plex runs fine on Windows 10 Plex app. Library shows a warning exclamation point and gives a “not found” when clicked on.
  • Plex app has trouble on FireTV. When user with added library is selected, there is an eternal spinner like the Samsung app. When user without added library is selected, some things work and others don’t.

It is driving me craxy that a perfectly running Plex system with 10 libraries should have trouble with adding a library.

Have you tried optimizing the database after adding so many movies at once? https://support.plex.tv/articles/226836308-help/

Yes. Database optimizing and Bundles did not help.

I then tried deleting all the movies and then deleting the library. Everything went back to working fine. Then I created a new folder and put three movies in it. I added a library for that folder. Added that library to a user. Same problem. I optimized the database and bundles. Same problem.

I don’t know why, but I did figure out how to work around this problem. I changed the name of the folder and the library to different names. Now it works. I am guessing it had to do with using the name of a library I had previously used and deleted. That seemed to be a problem.

That smells like a database issue.
I urge you to check and repair your database. If you let it slide, it may mean the loss of your library data in the future. https://support.plex.tv/articles/repair-a-corrupted-database/