Step 4: Consolidate the library

After changing your preferences, iTunes may or may not prompt you on whether you'd like to have your library organized and moved to the new location. Regardless of what delightful or baffling messages iTunes throws in front of you after closing the preferences window, the only way to really make sure your library gets transferred to the new location is to go into the iTunes File menu, scroll down to Library, and select "Consolidate Library" from the list of options.

Once you see a progress bar inching slowly across the screen as your files copy over, you know you're in business. This step could take awhile, so take a walk, read a book, or let iTunes work on the transfer over night.

Step 5: Confirm the transfer

At this point, your iTunes library has migrated to its new location on your external hard drive. To check if iTunes is working correctly and pulling your media from the new location, open iTunes, select a song, and select Get Info from the File menu. A window will pop up describing all the attributes of your song file, including the location of the file.

Now remember, iTunes hasn't deleted your old files, it just copied them to a new location. As long as your external hard drive is connected and powered on, iTunes will remember to grab your library from the new location. If your drive isn't connected, iTunes will temporarily default to the original location until your drive is connected again.

Step 6: Deleting old files (optional)

Keeping your original iTunes library around as a backup isn't a bad idea, but most people are motivated to move to an external drive for the sake of freeing up space on their computer. If you're feeling confident that your entire iTunes library has been safely copied over to its new location, there's no reason why you can't delete the files in the original folder.

Typically, PC users will find their original iTunes library content in this directory: C:\Documents and Settings\"USERNAME"\My Documents\My Music\iTunes\iTunes Music The default iTunes library folder for Mac users is: /Users/"USERNAME"/Music/iTunes/iTunes Music

Of course, we advise that you be cautious whenever you delete something from your computer. It's never a bad idea to backup your iTunes library to CD or DVD by using the "Back Up To Disc" feature in the iTunes File menu (located within the Library submenu). To be extra cautious, try trashing only a few files at a time from the original location, then launch iTunes and make sure the files you deleted still show up and play properly from their new location.

Be careful not to delete files from within the iTunes application, thinking you're deleting old files. The deleting we're talking about here is from within the Windows or Mac OS file directory. Also, be sure not to delete your "iTunes Library.itl" file if you to hold on to all the song ratings and playlists you've created over the years.

Bottom line, the only iTunes content you should consider deleting after copying your collection are the files within the "iTunes Music" folder located on your computer. Other files in the "iTunes" folder surrounding it are all worth holding on to.

Step 7: Dealing with missing data

OK, so you've deleted your old iTunes library and your new library running from the external hard drive is working great. But what happens when you go to run iTunes and your drive isn't connected? Don't panic. iTunes will notice your hard drive isn't connected and look for your library in its old location. Even though your old files are long gone, iTunes will not delete its record of the file simply because it can't be found.

If you try to play one of these missing files in iTunes, you'll get a prompt asking if you'd like to locate the file. Just say no. Once your external drive is connected back to your computer and you've relaunched iTunes, all your files will play just fine.

In the meantime, even with the drive disconnected, you can still use iTunes to stream music, and download new content from the iTunes store. Just remember to use that "Consolidate Library" command from step 4 once you've connected back to your external drive so that any new downloads you made while away from the drive get copied over to the new location.

Tags: Library, TV, external hard drive, audio book, CNET Networks Inc.