- Open a new Finder window.
- Navigate to ‘Applications > Utilities’ and launch the Terminal app.
- Type the following command into the Terminal window:
sudo nvram SystemAudioVolume=%80
- Press the ‘Enter’ key on your keyboard.
- Enter your admin password when prompted, and then press ‘Enter’ again.
If the above command doesn’t work for your particular Mac, then try repeating the above steps, but replace the Terminal command with one of the following:
- sudo nvram SystemAudioVolume=%01
- sudo nvram SystemAudioVolume=%00
- sudo nvram SystemAudioVolume=” “
If at any point you want to re-enable the startup sound, then simply launch a Terminal window and run the following command:
sudo nvram -d SystemAudioVolume