Hi there guys. I recently made this account because I have a sound control problem with my mac. He's never done this before and it's pretty annoying. The problem is that I DO have sound, but I cannot control the sound with my keyboard, nor with the sound control bar at the top right anymore. I have to control the sound by using system preferences or with a sound control bar on iTunes/Youtube ect ect. How can I fix this? I just want to be able to control the sound with my keyboard. It does respond when I hit the button, but the sound does not got higher or lower at all.