Auto-mute your Mac's speakers each time you turn it offGot this great tip from lifehacker. It actually turns off all sounds (mute) each time you shut down. Not the exact thing I was looking for (I only wanted to disable the one startup sound), but we've used it for a year or so on our Mac and love it.
Create a file named /Library/Scripts/mute.sh
#!/bin/bash osascript -e 'set volume with output muted'Then run these commands:
sudo chmod u+x /Library/Scripts/mute.sh sudo defaults write com.apple.loginwindow LogoutHook /Library/Scripts/mute.sh