I run audio from my PB through a usb audio interface (a synth) and into my stereo. Sometimes when i boot, the synth powers up from the usb but the sound comes out of the PB onboard speakers. When i check sound prefs, the USB interface is not listed. I also get this sometimes where a USB HD (on the other usb port) is not on my desktop when i go into OS X. A reboot sometimes resolves but sometimes doesn't, in which case I reboot with the devices disconnected and connect them once into the OS and they pick up ok. Do any of you guys know why this happens? Are USB power and 'data' dealt with seperately as i initially though if the PB successfully powered the devices, comms would also be ok. Is there any way to 'refresh' USB detection from within the OS, cos i reboot a lot and this keeps happening. I mean similar to refreshing devices in windows device manager. thanks guys, dren.