After 18 months of fighting with my sp2400, I gave up and went out, bought a new 3800.
I was getting constant "communication error" when using the 2400. paper profiles correctly chosen in the print setttings menu, Color management off, profiles choices made properly in lightroom. It never worked properly. So much wasted ink and paper.
I picked up a 3800 today and made about 10 prints on three different kinds of papers the first hour I set it up, all worked perfectly and I got fantastic prints.
I am a mac user (intel) 3 gigs of ram, two hard drives, two back up drives.
End of story.
Those of you contemplating a 2400 and you are on a Mac.
Don't say you have not been warned.
Get a 3800, it works perfectly