What you will achieve

Restore sound output and input when Mac speakers, headphones, or mic stop working.

Mac audio routes through Core Audio to built-in speakers, HDMI, USB interfaces, or Bluetooth. Wrong output device is the most common “no sound” cause after dock changes. Reset audio daemon before assuming speaker hardware failure.

1) Output device check

System Settings → Sound → Output — select MacBook Speakers or correct device.
Volume not muted — press F12 or use Control Centre.
Bluetooth headphones may be connected but paused — disconnect to test internal speakers.

2) Input device

Sound → Input — select built-in mic; speak and watch input level bars move.

3) Core Audio reset

sudo killall coreaudiod

Restarts audio daemon — reconnects interfaces.

4) Safe Mode and NVRAM

Boot Safe Mode — if audio works, remove third-party audio drivers (BOOM, virtual devices). Intel: try NVRAM reset for stuck output routing.

5) macOS update and hardware

Check Software Update for audio firmware. Persistent failure after OS update may need Apple diagnostics — left/right speaker cable issues on some MacBook models.

6) Aggregate devices

Audio MIDI Setup can create aggregate device that routes to wrong output — delete aggregates you did not create. Multi-output device sends same audio to headphones and speakers simultaneously for DJ use only.

7) HDMI and display audio

Monitor as default output has no volume keys — switch back to MacBook speakers in Sound when unplugging HDMI. Some docks need driver update for DisplayPort audio.

8) Bluetooth codec

Low-quality SBC codec on cheap headset sounds like distortion — check device supports AAC; remove and re-pair from Bluetooth settings.

Verify

Test tone in Sound settings plays; YouTube audio works; mic records in Voice Memos.

Additional troubleshooting notes

If steps above do not resolve the issue on the first attempt, reboot once, confirm System Settings → General → Software Update is current, and retry with a second administrator account to rule out profile or keychain corruption in your daily user. Document exact error text from Console.app with timestamp — vague “it still fails” without logs wastes support time. On Apple Silicon, re-test after full shutdown (not just restart) because firmware and Thunderbolt controllers reset only on cold boot. Intel Macs should repeat test in Safe Mode to bypass third-party login items. Before erase or keychain reset, verify Time Machine or clone backup completed — batch 3 guides assume Monterey/Ventura/Sonoma/Sequoia paths in System Settings; search Spotlight for renamed panes if your macOS version labels differ slightly.