回答“My headphone jack sometimes not responding to headphones.”My Macbook pro mid 2012 audio jack works fine until it goes to sleep. Before it goes to sleep I can insert the headphone in and out and the system will switch between them, no problem. After it goes to sleep, you can't change the sound output no matter what. If it was on the speakers it will stay there, that's it. If it was on the headphone it will stay there as well. Impossible to change. I've tried all the options here, including a clean install and replacing the audio jack. No luck so far. It's pretty obvious this is a software issue. Programmed obsolescence ? Who knows… If there anyone with any solution regarding this annoying issue, please let me know.