Just wanted to add that I just purchased one of these and hooked it to my Mac, after installing the software, and it did not work. Did a power cycle and tried plugging in to different USB ports and still no go. Left it connected for a while to my powered USB hub (which I had initially tried and it did not work) while I read this forum and then started up and everything worked fine. Might want to try hooking a couple dozen to a Mac laptop and seeing if any have a hard time coming up. Mac laptops are notorious for not being able to drive instruments via USB.