The apple tv library file cannot be saved. An unknown error occurred (-54)

Greetings XPaine,

Thanks for visiting the Apple Support Communities! It seems you're receiving an error while saving an item from your library in the TV app on your Mac.

To help isolate this behavior, I suggest to quit the TV app, and then reset the permissions associated with your user account. You can see those steps in the following support articles: Quit apps on Mac - Apple Support & Resolve issues caused by changing the permissions of items in your home folder - Apple Support

If further assistance is needed, it would be helpful to know the steps you're taking when you receive the error with your Mac.

Kind regards.

I tried this procedure both ways and it did not work. I had been getting this error for the past couple of days. I had not made any known system changes before I started to receive the error. Yesterday my library, which includes other video files that I had either created or purchased outside of the Apple Store, disappeared. The only things that showed up in My Library were my purchases from Apple. I had always been able to play these other videos through iTunes and subsequently the TV app. I tried to import one of the videos back into My Library, but nothing happened. I tried to open one of the videos using the TV app as the selected application, but nothing happened. I can still play the videos through other programs, but liked having everything centrally located in one program. I had read in one help recommendation about making sure your library is all located together. I maintain two different location because of the volume of content that I have to access and it hasn't proved to be an issue for the past 3 years (since I've owned this Mac). Any additional suggestions?

Have tried resetting permissions for my account in my home folder, but I'm still getting this error

Hi, I have the same issue. Went through the reset permissions/restart to no effect.

Are there any other options?

Is it possible to rebuild library?