Updating my itunes library
By default, i Tunes 12.2 and later doesn't create an i Tunes
If you're using OS X Mountain Lion or earlier or a third-party app that uses the XML file, you need to enable Legacy library XML support: The i Tunes file is no longer used by the latest versions of Apple media applications on OS X Yosemite and later. Contact the software developer for more information.
New versions of i Tunes are almost always better than the last—but not every time and not for every user.
If you've upgraded i Tunes and don't like it, you may want to go back to the previous one.
On a Mac, you update i Tunes using the Mac App Store program that comes built into the mac OS on all Macs.
Then, I selected all songs in i Tunes and deleted them (they didn't delete off of my original library location).
I then changed my library location back to where my music is located.
The i Tunes file is a database of the songs in your library and the playlists that you've created. If you delete this file, i Tunes creates a new, empty copy the next time that you open it.
Your playlists, song ratings, comments, or other information is lost.