Hi Tim, I'm getting this problem on my iMac - now several years old. I received the Infinity pedal today, and I'm getting the exact same problem. The pedal is no good to me like this, so I'll keep looking for solutions, but have a long job which I need to get on with. I believed all the 5* reviews, and am feeling a bit aggrieved at the time I'm wasting. Have you found anything out yet?