After updating my Mid 2011 iMac 21.5 to El Capitan today, I've noticed that my media keys, specifically Back (F7), Play/ Pause (F8), and Forward (F9) are no longer working. Most of the fixes I've found seem to involve a Google Music extension in Chrome which I don't have installed. I've tried looking through my iTunes preferences but didn't see anything that looked like it would fix the issue. Any ideas what I could try to get my media keys working again? EDIT: After logging out and logging back in to fix the stuck Calendar date, my media keys are back to working like normal.