A Solution of how to Permanently Disable (Mute) the Start-up Sound (Chime)

The following is a solution of how to disable the start-up sound.

In case it helps anyone, I have come across (and am using) a solution that works, (so far).

The solution is very similar to the one line terminal command mentioned on many forums, but this only worked temporarily for me. Then, a senior apple care advisor suggested tweaking it a bit. He advised that “%00” is not advisable, so use “%01” instead. Also, use the quotation marks, (some forums have the one line command without quotation marks).

So, this makes the final version (to be pasted into Terminal):

sudo nvram SystemAudioVolume="%01"

To revert everything back, just paste the following:

sudo nvram -d SystemAudioVolume

(I have never tried the terminal command to revert the sound back).

Hope this helps.

Thank you senior apple care advisor (you know who you are). And thanks to everyone else who posted the previous versions.

Silence and Peace...