My iTunes music files were taking up a lot of space on my MacBook, so I bought a WD Passport and transferred them to it. No problem--the location of my iTunes files shows up on my hard drive as being the Passport, etc. Only one small matter, though: The 22-odd GB of space has not been restored to my laptop's hard drive. Is there something I need to delete, or is it simply a matter of restarting my computer?