This feature is detailed in the main tutorial, which begins right below. Step 2: Open i Tunes → Preferences (Mac) or Edit → Preferences (Windows).
Step 4: Tick the box next to the option labeled “Copy files to i Tunes Media folder when adding to library”.
If you choose to prevent i Tunes from copying files to the i Tunes Media folder when adding items to your library, copying the entire i Tunes folder to an external drive won’t copy the referenced media files that live outside of the i Tunes folder.
That’s where i Tunes’ library consolidation feature comes to the rescue.
Consolidation ensures everything in your library is stored in one place.
You’re recommended to consolidate your library In other words, consolidating an i Tunes library ensures that every referenced media file gets copied when you drag the i Tunes folder onto an external drive.
You’d be amazed how much of your Mac’s storage is wasted on the i Tunes library.
All those apps and media you have purchased and downloaded over the years pile and clog up your Mac’s precious storage.
Apps and media you purchase, along with any files imported to i Tunes and all your interactions are kept in a special folder on your computer.
To locate the i Tunes folder on your Mac, choose Go → Home → Music → i Tunes in the Finder menu.