You didn't tell us what OS your running (9.2 or 10.??) or what version of Pro Tools (5 or 6). I'll assume that with the dual gig Mac, it's 10.?? which would mean that you need to be running PT6 (PT5 runs on OS9 and PT6 runs on OS10). If you're running either of these combinations then I would contact Waves. I too got the Demo cd but never used it. I bought the gold version and have had no trouble with them at all. It also might be helpful to know what else you have on your machine (software) and what you might have plugged into it. BTW don't unplug your mac when it's running unless it's absolutely necessary. Instead, push the restart button on the front of your machine). That way you won't risk some kind of an electical spike that might fry something important when you plug it back in. Good luck, Mike Studio17