Maximum Files or Directories

I just experienced this today.

I have a lot of videos on my 6TB drive.

I added a folder and 1 media file (MKV).

I connected it to my media player and tried to play it.

Then it showed an error message -

“There is no media available for playback.”

Structure for the particular folder in question is –

Videos \ Current (T-Z) \ MovieName \ Season 1 \ Movie.mkv

Is there a maximum number of readable directories or files with the media player?

Under normal circumstances, if I click the “MovieName” folder it would just go in and show the contents.

Note - no network or cloud involved – direct connection only.

Somehow when I renamed the folder, and made another one … the new directory was readable and the media was playable.

The older and renamed folder still showed the same error message.

Renamed From “MovieName” to “Movie-Name” – still not working
Made new Folder “MovieName” – working

I wonder what causes this.