Startup Sound

RolaAshraf wrote:

How can I disable my MacBook startup sound when I can't find this option in my sound effects panel?

The start up sound option was included in the macOS Big Sur system preferences, not before.

Depending on your Mac and macOS you can disable the start up chime from the Terminal.app copy and paste:

sudo nvram BootAudio=%00 

Mute start up chime in macOS Catalina:

sudo nvram StartupMute=%00

If you are on MacOS Big Sur you can follow the instructions in link below:

https://support.apple.com/en-us/HT211996