Q: How do I link my external hard drive, where my music is stored, to iTunes? I have changed the location of my music in preferences and it still does not locate the music.
A: Regardless of where you actual media files are stored, iTunes still needs to access the iTunes library database that provides the index of content. This file is normally stored in an “iTunes” folder under your “My Music” folder on Windows, or your “Music” folder on Mac OS X, however you can also tell iTunes to look for this file in a different location by holding down the SHIFT key (Windows) or OPT key (Mac) while starting iTunes.
So, if you have a copy of your iTunes library database on the external hard drive, you can either point iTunes to it directly, or simply copy it into the appropriate location on your local hard drive. Likewise, if you have the iTunes library database on another computer, simply copy it over to the new computer.
If you no longer have a copy of the library database, you will need to start a new iTunes library and reimport all of your media content by using the File, Add to Library option, or dragging and dropping it into iTunes.
Note that this will create a new library and you will therefore lose information such as ratings, play counts, and playlists in the process.
For more information, see our article on Transferring your iTunes Library..