I have a mid 2010 Macbook that I just bought. I was told the battery had expanded slightly (enough to slightly damage the case) thus the battery was removed. The battery icon indicates there's no battery. It works fine with the ac adapter. When it's unplugged, even for overnight, and then I plug it in and hit return, or the space bar, something to wake it up, it's instantly ready to go. Safari is running like I was when I unplugged it and it's still connected to the internet. I also have a mid 2010 Macbook Pro that has a dead battery since I bought it several years ago. I taped the ac adapter so that I can't accidentally knock it out, because if I do it needs to reboot OS X from scratch. That's the way all my other Mac laptops with dead batteries have been. Even when I wake my Macbook Pro up and it's still on Safari where I left it, if I do a refresh it will say it's not connected to the internet first before connecting and refreshing. The new Macbook doesn't need to do that, it's still connected to the internet. How is it that the Macbook I just bought is not completely losing everything when it is unplugged? With no battery, where is the power coming from and why is it different from my Macbook Pro?