Nothing has changed on my computer (Macbook) or iphone (4S) but now it won't sync. I usually sync wirelessly but even tried plugging it in. It displays the message: The iPhone Chris' Iphone cannot be synced because there is not enough free space to hold all of the selected items (additional 8.16 GB required). The capacity bar at the bottom shows that the phone is within capacity and I've got the "Sync only checked songs and videos" button clicked. It's a 16 gig phone that shows a capacity of 13.60 and 1.57 free. Any ideas?