The Acoustic Annoyance Vector
Since the very first Macintosh, Apple computers have announced a successful boot sequence by playing a loud, sustained, and highly recognizable musical chord. While this chime serves as a useful diagnostic indicator that the hardware is functioning correctly, it is completely unacceptable if you are powering on your laptop in a quiet university lecture theatre, a library, or a bedroom while someone else is sleeping. You must suppress this hardware-level audio trigger.
How to Disable the Startup Chime
Modern versions of macOS finally include a simple, graphical toggle switch to permanently silence the boot sequence, completely replacing the complex Terminal commands required in older operating systems.
1. Click the Apple Logo in the top-left corner of the screen.
2. Select System Settings from the dropdown menu (or System Preferences on older versions).
3. In the left-hand sidebar, scroll down and click on Sound.
4. Look at the main pane, specifically under the “Output & Input” and “Sound Effects” sections.
5. Locate the toggle switch labelled Play sound on startup.
6. Click the toggle to switch it to the Off position.
The operating system immediately saves this preference directly to the computer’s Non-Volatile Random-Access Memory (NVRAM). The next time you shut down and press the power button, the screen will illuminate, the Apple logo will appear, and the entire boot process will execute in absolute, total silence.