OK...so my Logitech K760 solar keyboard's inability to stay charged was starting to annoy, so I switched back to the Apple Wireless Keyboard that came with my system (2010 iMac). However, none of the media keys were functioning correctly, and I was missing the option "Use all F1, F2, etc. keys as standard function keys" in the keyboard prefs. All the media keys did was give the alert noise. Thinking the Logitech system had something to do with it, I removed the Logitech prefpane and rebooted. Nothing. I repaired disk permissions (since I hadn't done it in a while anyway) and rebooted. Nothing. I decided to plug in my older Apple Wired Aluminum Keyboard (came with a 2006 Mac Pro) and it worked. My preference option was back in the keyboard prefs and the media keys functioned as expected. So now I'm wondering why it is treating my wireless keyboard weirdly. I've unpaired and repaired with no luck. I also noticed that it is not reporting battery percentage, so I replaced the batteries. Nothing. Since I figured it couldn't do much to hurt the situation, I went ahead and upgraded to Mavericks today, and that also did nothing. My wired keyboard works fine, and my wireless keyboards works perfectly with the exception of the media keys. Any ideas? TL;DR My Apple Wireless Keyboard's media keys are not working. Help!