How do I permanently mute the start-up sound?

Look to the right side ------------------>

at the column "More Like This."

As an aside... Note that if you shut off your computer every day instead of letting it sleep; it will not be able to run the nightly maintainance scripts that keep the system runniing smoothly. You will need to find a way to remember to and to run the scripts during the times you have the computer powered up. There are some small 'utility' programs that can help with that.

Also a couple of those utility programs give you access to a hidden setting that will mute the chime.

You say "I don't consider it neither environmentally friendly nor economical to always use sleep"

But you should consider that sleep is the way the systems are 'made' to work. Also that they use so little power when sleeping that the startup tasks of spinning up and accesssing the disc, etc. and booting the operating system generally will use more power (or at least that is the common thinking, I don't have data I can cite to prove it).

" I will have to plan when my mac is going to crash either way"

As a former windows user I can see how you might think that but it is not a problem with an Apple machine.

I ran my last computer for 3 year only rebooting when installing software and no crashes except when I dropped it on a brick sidewalk (and it ran for a year after too).

This computer is 4 years old and I run it the same way. It has only crashed once when I installed the Mac Defender program without doing my homework first.

"As an aside... Note that if you shut off your computer every day instead of letting it sleep; it will not be able to run the nightly maintainance scripts that keep the system runniing smoothly."

That was years and OS's ago. They'll run as soon as you boot it up.

Try this.....

Open System Preferences/Sound

Click the Output tab

If you have external speakers plugged in you should see Headphones as an output device. Select it and slide the Output Volume all the way to the left (Mute).

Unplug the external speakers. You should now see Internal Speakers as an output device. Select it and slide the Output Volume all the way to the left (Mute).

All sound devices should be muted. Restart your system to test.

I have been using an app from Arcana which You can get from this web site

http://www5e.biglobe.ne.jp/~arcana/index.en.html , it has worked on my 2008 Intel imac with Leopard through Mountain Lion. I have had to update it at least once. You can adjust the chime volume or mute it all together. I have mine very low in case I were to need the indicator chime Hope this helps

Take a look at this app:

Cocktail app can turn off the startup sound in Mountain Lion.

http://maintain.se/cocktail

Been using this app for 7 years with no problems. Updates and upgrades are free.

But it is part of this thread - You made sleeping you made the prima facia reason for the thread when you went off on "I am not going to be forced to use sleep by an annoying start-up chime either" as the reason why you wanted a silent bell. (and I was only trying to help - not looking for a remark)

And I stand corrected - I still schedule my maintainance to run with a utility or terminal commands and

never realized they now ran on startup. Thaks Sig.

That said, I won't be responding here anymore.

You have already been given the solution in the above by a few people.

Here is how to mute the startup sound using terminal commands...

http://osxdaily.com/2012/11/04/disable-mac-boot-chime/

NP

btw - not sure why you marked me as solved your problem

feel free to give someone else the points