I have a macbook pro running lion 10.7.5. Occasionally, my keyboard backlight buttons will not respond while taking off Apple Keyboard Cover. I've been looking all over the place for a solution but none have worked. Also, while most people report seeing a "no" symbol when trying to use the buttons, I'm not getting this. I have the light-sensing setting turned off, so i should be able to light up the keyboard regardless of how bright it is around me. Can anyone tell me why this might be happening, and how to fix it? It's been going on for a while now.