There can be many reasons why you want to mute your Mac while booting. The loud “bong” sound can be quite annoying when you are in a meeting or classroom, and turning on your MacBook Pro or MacBook. It is however possible to change the volume of the startup sound, or even completely disable it if you are looking for that option. There are several ways to do this; I’ll guide you through three of them.
Holding the Mute-button: If you are using a newer Mac with a new keyboard, you can just keep holding the ‘Mute’ button while booting your system. You will need to keep holding this button until the Apple logo will appear on your screen. This will however only temporarily mute the sound, and it will be loud again at the next reboot.
Changing the volume: You can also turn down the volume before you shutdown your Mac, this way you will not hear the “bong” sound but you will have to change the volume if you want to hear anything at all. Not the best way, and especially annoying if you are sharing the system with others, who may not know what the problem is.
Full-control: If you want to take full control, and make changes that will stick. We suggest that you use the application StartupSound.prefpane, this cool app lets completely mute the startup sound or change the system volume. There are more similar applications available, but there isn’t one that comes close to the easiness of StartupSound.
Use this application if you want to disable the startup sound of your Mac under Mac OS X Lion.