The experience many of us have with a fragmented library is clicking play on a song and an exclamation mark comes up (!), along with an error saying iTunes can't locate the song. The other thing that happens is you have a ton of songs on your computer that live in the 'Unknown Artist/Unknown Album' folder... a digital dumping ground for anything iTunes doesn't know what to call because it's missing the all important 'meta data' or name of the artist and album from which the song comes.
To help with prevent these issues, there are several important tools to be aware of. The first tool is in the iTunes preferences panel. Please refer to 'Working with iTunes Part 2' if you don't know how to find your iTunes preferences. When you get into the iTunes preferences, click on the Advanced tab and look at the options 'Keep iTunes Media Folder organized', and 'Copy files to iTunes Media folder when adding to library'.
These two options are often responsible for helping to create a lot of mess on your computer. Let's say you just downloaded music from a friend's thumb drive (heaven's no, that's illegal!). You probably did this by copying the music on to your desktop, then adding the songs to iTunes by dragging and dropping them into the iTunes library. If these two settings are turned on, iTunes will first create duplicate copies of the songs, and any song that doesn't have an artist name or title, will be copied into the Unknown Artist, Unknown Album folder in your iTunes Music Folder.
This can create a mess because not only do you now have two copies of each new song you just got from your homie, but one of them is no longer identifiable because it's in an anonymous folder.
Yet these two options do elp if you're aware of how they can work for you. Let's say you've just purchased music from Yogi Tunes and downloaded your new tunes into your downloads folder. When the download is complete and you unzip your purchase, drag and drop into iTunes. If both of these options are turned onhed iTunes will make a copy of the files and placed them neatly in folders by Artist and Album name. All of our downloaded music has the correct information stored in the songs, so that iTunes knows where to put it in it's own file system. As a final step you can then DELETE the original files in your downloads area!
For those of you who have messy iTunes libraries, and tons of duplicate songs by Unknown Artists, there are several third party tools available for cleaning up your library. Song Seargant, and Tune Up are two that I've had recommend to me, although I've never tried to use either they both get good reviews from users. They remove duplicates and track down artwork and song information for music on your computer that is missing these critical items. Of course no fix it software is perfect, so there may be some left over fragmentation, but after reading this article and spending a bit of time cleaning up your computer you should be far better off than you were before!