It's been mentioned and I personally thought some people didn't know how to set it up, that the drive falls asleep and it actually does. There is no option to change this as it manages its sleep mode independently from OS option for sleep priority. WD offers no solution to change this, no software, no firmware. I don't know about coupling it with Mac but I'm using Win7-64bit on a powerful workstation and hooked it up through esata to get the best performance. Disappointing to say the least. it created all kinds of problems and I had to reformat a couple of times and lost some material as it got corrupted due to latency when it fell asleep. I'm in the process of returning the drive and so I'm letting you know I'm done with this product. Hope some of you are happy with it and that it serves your purpose but it's not going to be for me. I do video, post-production, photography, illustration, and will be looking for a better more solid solution for my priceless work.