Usually I start out my answer by assuring you that it’s nothing you did, but in this case there’s a subtle setting in the Mac OS X system Sounds control panel that’s changed and, well, it’s quite likely that it’s something you’ve changed without realizing it. It’s okay, though, no judgment, and it’s easy to fix. 
To start, launch System Preferences… from the Apple menu on the top left corner of your MacBook screen.
It pops up a window with lots of icons. Look for this row:
In this case, it’s Sound that you want, so click on that.
The Sound system preference opens up and it’ll look like this:
Click on “Output” along the top and if your headphones are plugged in, you should see them (or, as I see, the AudioEngine D3 digital audio converter that makes my audio sound 10x better):
Now that you can see that’s set properly, go back to Sound Effects and look more closely at the “Play sound effects through” setting. There are a couple of choices:
Select “Selected sound output device”, as shown, and you’ll solve the problem forever. Or at least until it mysteriously changes again.
The post Why is my Mac system beep not going to my headphones? appeared first on Ask Dave Taylor.
