I just looked on M-Audio's web site, where they list driver downloads. It seems that NOT ONE of their products has a Mac OS X 10.5.6 driver. According to their site support ends with 10.5.5 and even then 10.5.3, 10.5.4 and 10.5.5 are listed as "beta" drivers for the Fast Track Pro. Does M-audio equipment really not work with the current release of Mac OS X? Or maybe the web site is out of date. I'm still looking for an interface and I see something wrong with every one I look at. Maybe I'll have to move my budget up past the $200 level.