Check out an assistant for muting of completely silencing system startup. Access the parameters of a default chime that plays at launch. Work with the structure and permissions in different versions of your operating system. Replace individual signals according to your needs.
Downloading StartNinja 1.0.1 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. The bundle identifier for this application is com.allvu.StartNinja. The software relates to System Tools.
This free Mac application was originally created by allvu. The following version: 1.0 is the most frequently downloaded one by the program users. Startninjainstaller.dmg is the frequent file name to indicate this app's installer. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
Macs don't have a built-in way to mute or silence the system start up chime. If you’re in a library or coffee shop you don’t always want that start up chime to play. Now you can silence the Mac OS X(Mountain Lion and Mavericks) start up chime with StartNinja. It is a free and simple desktop utility that silences the start up chime and will resume previous sound level after logging in.
You may want to check out more Mac applications, such as Cinch, Overflow or BOINCManager, which might be similar to StartNinja.