After installing Mountain Lion my MacBook sometimes freezes when I open it. This seems to happen most regularly when the laptop hasn't been used for a while. So when I open it in the morning it nearly always happens. When I open the lid the screen comes on and I can see the login screen but the keyboard and trackpad just do not respond at all. I end up having to hold down the power button and hard reboot. This is happening on my own MacBook Pro, but it is also happening on my wife's MacBook Air. I asked three of my work colleagues about this and they all report that it is happening to them with Mountain Lion too. Two of them had MacBook Pros, one retina and one last year's model, whilst another had an Air. So this seems to be a Mountain Lion problem and isn't affecting just one model. Is anyone else seeing this problem, and does anyone know how to fix it?