there's a mobile backup folder...can't see what's in it...but it's using up a ****-load of space on the drive (which is at a premium on the 128GB model, of course).

i don't have my iTunes stuff on this mac...it's on my other mac desktop...weird. and i did plug in my phone, but haven't synced it with this macbook since it's synced on my desktop.
not sure what it could be from then...
but i just backed up to time machine 20 minutes ago....it shouldn't be that large.
and i haven't synced on this computer yet with my iPhone so it can't be that.
Did you migrate this setup from a previous mac?