To save your itunes library on a backup hard drive here is the method by support.apple.
Step 1: Consolidating Your iTunes Library
To make the move as easy as possible, it’s important to make sure all of the items in your library are in one place.
- Open iTunes Preferences:
Mac: Choose iTunes > Preferences.
Windows: Choose Edit > Preferences. - Click Advanced.
- Make sure the option to “Copy files to iTunes Media folder when adding to library” is selected.

- Click OK.Note: After you click OK, iTunes copies any music files that weren’t in the iTunes Music folder, and places the copies in the folder. The original files are left in their original locations. To save space on your hard disk, you might want to delete the original files.
- Choose File > Library > Organize Library.
- Select the option to “Consolidate files.” Note: If you recently updated to iTunes 9, you might want to consider selecting the option to “Upgrade to iTunes Media organization.” This updates the file organization of your iTunes Music folder.

- Click OK.
Step 2: Copy iTunes folder to your external hard drive
To copy all the items in your iTunes library (including the iTunes Library file that holds all your playlists, playcounts, ratings, and other data) to your external hard drive, follow these steps:
- Quit iTunes.
- Locate your external hard drive.
Mac OS X: On the desktop or Finder sidebar.
Windows: In My Computer - Locate your iTunes folder:
By default, the iTunes folder is located in:
Mac OS X: /Users/username/Music
Windows: \Documents and Settings\username\My Documents\My Music\If the iTunes folder is not in the default location listed above then you can find where the iTunes folder is located by following these instructions:
- Open your iTunes Preferences:
Mac: Choose iTunes > Preferences.
Windows: Choose Edit > Preferences. - Click Advanced.
- The location of your iTunes folder will be listed in iTunes Media folder location box, as pictured below.





