So this has been happening more and more for the past few days, and I don't know what's going on. On my Macbook Pro, my keyboard would sometimes stop working, but wait!, it's not ALL the keys, it's ONLY the letters and numbers that stop working. Furthermore, I use a wireless Apple keyboard, and when this occurs, both the bluetooth and the Macbook Pro keyboard freeze up at the same time. What's even weirder, In some instances when it wakes up from sleep, HALF of the keyboard would be working, the other half not. Also keys such as caps lock ends up not working, or mapped to another key... Has anyone else experienced this strange behavior? I'm hoping it's not a hardware issue, due to the fact that BOTH keyboard fail at the same time. EDIT: Solved the problem, it was the "Mouse Key" setting within Universal Access, it disables all letters and numbers on the keyboard. I was pressing it 5 times when I was doing work on Illustrator, and that must've turned it on.