Hi Eric! I'm not familiar with the MotU USB MIDI Interfaces. But with my Unitor8 MkII I need to install a special Unitor8 USB driver for MacOS9 in the system extension folder and a Unitor8 OMS driver in the system/OMS folder to get the interface recogniced. When there is no special OMS driver available for your interface you need the "Standard Interface OMS driver" in your system/OMS folder. Make sure other USB drivers and system extensions in MacOS9 like "HID Library", "InputSprocket Classic", "InputSprocket Extension" and "USB Device Extension" are enabled. When I did my new set-up in MacOS9 the USB port wasn't shown - only the printer and modem port. When I let OMS search for new devices it found my Unitor8 flawlessly on the USB port. Make sure you've got the preference pane "OMS preferred device" enabled. Chose your MotU interface there. Open for a change your system profiler in MacOS9 - does it show other USB devices you've got connected. When not - we need a deeper look into your system extension... Cheers groba