At first I only needed to connect a master keyboard to drive Kontakt 2. So a friend lent me his usb uno no longer using it, but I got the famous bug of operation we are talking about on the forums (poor responsiveness and keys that are locked) and that on both my G5et on my macbook pro core duo.
I thought it came from the Mbox, but without the same problem.
I sent an email to M-audio and no new after three weeks.
config: G5 1.6 Ghz 2GB Ram 750 GB HDD, Macbook Pro Duo 2Ghz 2GB 100GB Rope 7200trs, Mbox, Protools 7.1, Kontakt2.2, Keyboard Roland PC 180-A

UTILIZATION

I loaded the latest drivers and whether in ProTools, in Reason in Kontakt, it never really worked properly.

OVERALL OPINION

I'm really surprised they can sell such an interface and above all there can be such a bug.
I just needed to connect a master keyboard which was working fine on my old G3 with a midi interface in serial port.
I fell back on an Edirol UM-3EX who has more drivers for Intel Mac (not on the cd, but to download from the site) and that worked immediately and perfectly.

I insist. I really tried everything.