audioheadphoneskeyboardmacbook pro
I have a mid-2012 MacBook Pro Retina, and am using QuietComfort20 headphones that previously used to work.
Now, after a clean install of OS X Yosemite, I'm unable to use the headphones, no audio comes through them at all.
When I adjust the volume use F11 or F12 I get the following
The headphone jack had a red LED glowing inside, which clued me in that it thought there was an optical cable plugged in. Plugging and unplugging a pair of headphones resolved the problem.
Well I actually just figured this out. In Preferences under Mission Control there were two options set to use the F11 and F12 keys. I set these to '-' and that fixed the issue. The options that were set to use these function keys are highlighted in the screenshot below.
Best Answer
Seems that the Audio Output selector was "Parallels Access Audio". When I used parallels access apparently the default output was changed, and not reverted.