Yesterday my MacBook’s audio output turned red and macOS started behaving strangely. The symptoms are as follows:
- no sound from built-in speakers (when macOS is loaded);
- there is no way to adjust the volume;
- sound plays only through headphones or external speakers;
- the headphone jack lights up red.
As it turned out, the matter is in the closure of the contacts in the headphone jack. And the solution is extremely simple – we take a toothpick and carefully touch the inner walls of the connector, after that everything should work fine. It helped me, so try it.