Your Mac's sound stopped after sleep, or cuts out at random

Why it happens

All sound on your Mac goes through one background service called Core Audio. Now and then it hangs, often after sleep, an update or a device being plugged in or out, and then every app goes silent or the sound stutters. A restart starts Core Audio fresh.

How to fix it

1. Save your work, then choose Apple menu > Restart… and click Restart.

   Apple menu›Restart…

2. When you're back, open System Settings and click Sound. Under Output, click the device you want to hear, such as your Mac's own speakers or your headphones.

   Sound›Output

3. Drag Output volume up and make sure Mute isn't ticked, then play something to test.

Still not fixed?

1. If sound comes back after the restart but disappears after the next sleep, check Sound > Output each time you wake the Mac. Monitors, docks and Bluetooth headphones can take over the sound when they reconnect.

2. Silent in only one app or browser tab? Quit that app with Command-Q and open it again, and check the tab isn't muted.

3. Unplug USB audio gear, docks and hubs for a test. A device that drops out can take the sound system down with it.

4. Install any waiting update in General > Software Update. Sound bugs are often fixed in point releases.

   General›Software Update

5. If the speakers crackle or stay dead even after a restart, run Apple Diagnostics. On a Mac with Apple silicon, shut down, press and hold the power button until Options appears, release it and press Command-D. On an Intel Mac, press the power button and hold D. If it finds a speaker problem, that's hardware: contact Apple Support or book a repair.