Fix MacOS Sierra Audio Issues: Step-by-Step

If you’re running macOS Sierra and suddenly have no sound, crackling audio, or a missing output device, this guide walks you through the most common fixes. From simple volume checks to resetting the core audio process, these steps resolve the majority of Sierra audio problems without needing any special tools.

What You’ll Need

Your Mac (obviously)
Admin user account (for some steps)
A few minutes of patience

Step-by-Step

Check the basics first. Click the volume icon in the menu bar and ensure it’s not muted and the volume is turned up. Also, check if you’ve accidentally selected the wrong output device (like a Bluetooth speaker that’s off) by going to System Preferences > Sound > Output.
Restart your Mac. It sounds cliché, but a quick restart clears temporary glitches in the audio system. Save your work, then choose Apple menu > Restart.
Quit and reopen the app. If only one app has no sound, quit it (Cmd+Q) and reopen it. This often fixes audio issues caused by the app itself.
Reset the Core Audio process. This is the key fix for many Sierra audio issues. Open Activity Monitor (in /Applications/Utilities), search for “coreaudiod” in the search box, select it, and click the X button in the toolbar to force quit. It will automatically restart, and your audio should come back.
Check your input and output settings. Go to System Preferences > Sound > Output. If you see a list of devices, select the one you want to use. If nothing is listed, your audio hardware may not be detected. Also, check the Input tab to ensure the correct microphone is selected.
Reset the NVRAM (Non-Volatile Random-Access Memory). This stores sound volume and other settings. Shut down your Mac, then turn it on and immediately press and hold Option+Command+P+R for about 20 seconds. Release when you hear the startup sound a second time (on older Macs) or see the Apple logo appear and disappear twice (on newer models).
Run First Aid in Disk Utility. Corrupted system files can cause audio problems. Open Disk Utility (in /Applications/Utilities), select your startup disk (usually “Macintosh HD”), and click “First Aid”. Click “Run” and let it finish. This may take a while.
Reinstall macOS Sierra. If nothing else works, reinstalling the operating system (without erasing your data) can fix deeper system issues. Restart, hold Command+R to enter Recovery Mode, and choose “Reinstall macOS”. This will keep your files but replace system files.

Common Mistakes

Forgetting to check the output device: Many people assume the built-in speakers are selected, but a Bluetooth device or HDMI display might be the chosen output, and if it’s off, you get no sound.
Not force-quitting coreaudiod properly: Just closing Activity Monitor after selecting it won’t do anything. You must click the X button and confirm the force quit.
Skipping the NVRAM reset: Some users try only software fixes and miss this hardware-adjacent reset that often solves volume and output issues.
Assuming it’s a hardware problem: Most Sierra audio issues are software-related. Don’t rush to the Apple Store before trying these steps.

Tips

Use the Option key for quick access: Hold the Option key while clicking the volume icon in the menu bar to see your input and output devices directly.
Create a separate user account to test: If audio works in a new user account, the problem is likely with your user’s preferences, not the system. Go to System Preferences > Users & Groups to create a test account.
Keep your Mac updated: Apple released several updates to Sierra that fixed audio bugs. Check for updates in the App Store.
Check for third-party audio drivers: If you use external audio interfaces or USB sound cards, visit the manufacturer’s website for Sierra-compatible drivers.

Troubleshooting

If the steps above don’t resolve the issue, here are additional things to try:

Try a different user account: As mentioned, this helps isolate the problem. If audio works in the new account, you can delete the problematic preference files in your main account (like com.apple.soundpref.plist in ~/Library/Preferences).
Check for external devices: Unplug all USB, Thunderbolt, and HDMI devices. Sometimes a faulty device can interfere with the audio system. If audio returns, reconnect devices one by one to find the culprit.
Boot into Safe Mode: Restart your Mac and hold the Shift key. Safe Mode runs a disk check and loads only essential extensions. If audio works in Safe Mode, a third-party extension is likely the cause. Restart normally to exit Safe Mode.
Check the sound card: If you have a Mac Pro or an older iMac, the internal sound card might be loose. This requires opening the computer, so only do this if you’re comfortable with hardware.

Frequently Asked Questions

Why does my Mac have no sound after updating to Sierra?

Updates can sometimes reset audio preferences or cause conflicts with existing drivers. The coreaudiod reset (Step 4) usually fixes this immediately.

How do I reset the audio on my Mac?

The quickest way is to force-quit coreaudiod in Activity Monitor. It restarts automatically and reinitializes all audio hardware.

Why is my Mac’s volume greyed out?

This usually means the Mac doesn’t detect any audio output device. Try resetting NVRAM, checking for external devices, or reinstalling macOS if the issue persists.

Can I fix audio issues without reinstalling macOS?

Yes, most issues are fixed with the coreaudiod reset or NVRAM reset. Reinstalling is the last resort.

Why does my audio crackle or pop?

This can be due to a sample rate mismatch. Go to Audio MIDI Setup (in /Applications/Utilities), select your output device, and try changing the sample rate to 44.1 kHz or 48 kHz.

Why is my Mac’s microphone not working?

Check the Input tab in Sound preferences, ensure the correct device is selected, and check the input volume. Also, check if any app has exclusive access to the mic.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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