I have been on Yosemite DP 4 for about 2 weeks now, even went on vacation on the dp with no major issues. However in the last day or two since I got back my audio will completely stop working. I will see the volume changer popup on the screen but I get no audio or pops when I change the volume via the keyboard. I have to reboot to fix the issue. Has anyone else had this problem. I am on a 2013 Retina Macbook Pro 13"