Stop the Mac Startup Sound
Mac’s have a very distinct startup sound that chimes whenever they boot, this is fine for most people but if you’re in a quiet office or library it can be very obnoxious to have the loud startup sound announcing to the world that you are on a Mac. Thankfully there’s a nice little utility that’s easy to install and works just like any other Preference Pane on your Mac. Aptly named StartupSound lets you adjust the volume of your Mac’s startup sound, and of course to stop it chiming and mute it entirely.
Installation is really easy, you just need to double-click it to install the Preference Pane, then if you want to stop the Mac startup sound simply click the ‘Mute’ button alongside the volume slider. StartupSound works in Mac OS X 10.4, 10.5 and 10.6.
Because of it’s ease of use and seamless integration into Mac OS X, I recommend StartupSound. However, I have heard reports that the StartupSound preference pane doesn’t work for everyone for whatever reason, it works on every machine I’ve installed it with but obviously your mileage may very. If you are having troubles with StartupSound, try another app called Psst which also mutes the Mac startup sound, it’s just a tiny application that runs and is very easy to use.