Q: There seem to be two copies of my 31GB iTunes library on my Mac mini. When I right click “Macintosh HD” it says I’ve only got 9GB of space remaining. Can I delete one copy of my library without losing iTunes functionality (syncing w/ 5G iPod, creating & editing Playlists, etc.)? How do I go about doing this?
A: Actually, chances are that you only have one iTunes library in terms of the music that is actually being used by iTunes. If you’ve imported your music into iTunes from another folder (ie, by using the File, Add to Library function), then you probably have two copies of your music as iTunes has copied each track into your iTunes library and left the original where it was.
It’s important to keep in mind that iTunes tends to err on the side of caution when it comes to deleting or moving files. iTunes will not delete or move any music track or file that is not located in your iTunes Music Folder, since it considers these files to be outside of its control. Therefore, when you import music files from another location, iTunes makes a copy of the file and places that copy in its own iTunes Music Folder, leaving the original where it was.
In the default iTunes configuration, the tracks that are used by iTunes itself are stored in your iTunes Music Folder, which is located within your “Music” folder (Mac) or “My Music” folder (Windows), under iTunes/iTunes Music.
If you have not changed your default settings, then it is very likely that the tracks in here are the ones that iTunes is using. Any other music tracks that you have on your hard drive outside of this location are not being used by iTunes, and can safely be deleted unless you have some other reason to keep them in those locations.
Note that you can change the behavior of iTunes in regard to how it handles the importing of music files by going into the iTunes Advanced preferences tab:
In this dialog, you can change the location of the iTunes Music Folder, as well as the setting for whether or not iTunes copies files into the iTunes Music Folder. If you DE-select the option to Copy files to iTunes Music folder when adding to library, then iTunes will simply create a reference to any new files you import from their original locations (wherever you placed them on your hard drive), rather than making an additional copy of them.