libgdx -- Gdx.files.internal(); --> File Not Found

What worked for me is, I had to go into assets->Build Path -> Configure Inclusion/Exclusion. I had to add all of my needed folders and files into the Inclusion section.

Try "cleaning" your project by going to Project-> Clean. Also try "refreshing" your libGDX desktop folder by right clicking and using Gradle-> Refresh All

libGDX uses linked folders. You only need to copy the file to one of your asset folders (do this in eclipse, not in file explorer.)