Then how come my MacBook Pro 3,1 from 2007 has no heating issues, and had none since Tiger??? If it really was an operating system update issue, you'd think it would have surfaced some time between Tiger and now on ALL machines. It has not. I push my MacBook Pro to the limits by running dozens of things at once, and not once has it unexpectedly shut down. So before you push the blame to Apple's operating system update testing process, recognize this is not an easily reproducible problem. If it was, sure Apple would have fixed it a long time ago. But it isn't. So stop pushing the blame on Apple, when we run many tens of thousands of applications, have billions of circuits on our RAM, and trillions of tracks on our hard drive. And recognize unless the issue is one that reproduces readily, it is unlikely any update can fix it. Consider what 63 factorial is on your calculator. 10^99. There haven't been that many seconds in the age of the universe. For Apple to isolate every possible combination of hardware and software malfunction they'd have to be omnipotent spanning many trillions of universes just to have the time to do so. That's why Apple develops specs: http://developer.apple.com/ And if certain hardware and software vendors fail to meet to those specs, there is nothing Apple can do about it, as they can't isolate every possible combination. The best you can hope for is a happy medium met during the warranty period. It is amazing there aren't more failures. And Apple will mail you a box to return your machine to a repair shop, with as little as a 36 hour turn around time if the Genius bar, authorized service center policies are too inconvenient for you. So call AppleCare. And remember, this is a user to user forum. Enunciating your issues here only brings it to the alert of other users. I've spoken to Genius bars and they tend to disregard Discussions. So please call AppleCare if you think you have an issue, and don't blame Apple or ask for Apple's help on this board. We are just end users here, and blaming gets people nowhere.