works fine with current downloadable driver (now August 2008)written a while back for Tiger. Using half CPU cores with only a dozen tracks at low latency but it works (interface MI4 USB1.1, fast asio2 driver eats CPU). If you have other audio or midi devices eg bus-powered midi controller do not use USB splitters and live without the mouse. Otherwise buy platform sharing interface. That is what I am going to do, Audacity is all very well but I want Wavelab Lite as one editor and use Cubase 4.1 anyway. Tiger leaves out a few modern fundamentals, like "auto Put Away/Eject USB device" setting, I notice XP USB2 gets better mileage out of external USB2 (IDE) drives and USB2 bandwidth and connectivity in general. Why is this? A Tiger bug? I am a fan of no commercial OS. As it happens my controller and interface are USB1.1 and happy but that means no audio drive until a Lacie... so the price rises. OS X is better than XP but kind of all over the place, like the planet, they both plod along