How do I silently start up my MacBook Air?

Solution 1:

Plugging in headphones used to be the quick and dirty way to assure silence (back in the PPC hardware days).

Now, the self test startup chime still uses the internal speaker whether or not the headphone jack is in use, but the below trick will work on older macs. It is of use with new macs as long as you don't set your mac to reboot automatically and you don't forget about the current behavior and reboot it yourself.

I have a snipped nub of a headphone jack that I use when I am in a place where noise is prohibited no matter what the software decides.

You can get a plug without any cord for less than $5 at a store such as Radio Shack if you don't have headphones you can sacrifice or the cut cord doesn't please you.

It's simply not possible to change the NVRAM mute/volume setting after the mac is shut down (or sleeping) so even if you prepare properly, sound will be made if things don't go as planned on the shutdown.

Solution 2:

For Snow Leopard and earlier machines download and install "StartupSound.prefPane" which will install a preference pane in system settings to allow you to adjust the startup volume and disable the startup sound:

http://www5e.biglobe.ne.jp/~arcana/StartupSound/BETA/index.en.html

Note that the above has mixed results in Lion. For Lion users the following is recommended:

1. Login as administrator and open a terminal window

2. Create scriptfile for muting

   sudo nano /path/to/mute-on.sh

3. Enter this as content, when done press control+O to save and control+X to exit:

   #!/bin/bash
osascript -e 'set volume with output muted'

4. Create scriptfile for unmuting

   sudo nano /path/to/mute-off.sh

5. Enter this as content, when done press control+O to save and control+X to exit:

   #!/bin/bash
osascript -e 'set volume without output muted'

6. Make both files executable:

   sudo chmod u+x /path/to/mute-on.sh
sudo chmod u+x /path/to/mute-off.sh

7. Check if any hooks already exist (these will be overwritten, so make sure it is OK for you)

   sudo defaults read com.apple.loginwindow LoginHook
sudo defaults read com.apple.loginwindow LogoutHook

8. Add hooks for muting

   sudo defaults write com.apple.loginwindow LogoutHook /path/to/mute-on.sh
sudo defaults write com.apple.loginwindow LoginHook /path/to/mute-off.sh

Notes:

• /path/to/ is the location of the scripts, I used /Library/Scripts/
• you can skip the unmuting loginhook (i.e. each logout will silence your machine), but I like it this way because I always have sound available exactly at the volume level I set last time
• root has to be the owner of the script files - running an editor from command line with sudo is the easiest way to achieve that (otherwise you need to chown)

• to delete the hooks, use the following:

  sudo defaults delete com.apple.loginwindow LoginHook
sudo defaults delete com.apple.loginwindow LogoutHook

(source)

Solution 3:

This is the only thing that worked for me under OS X 10.8.5 (Mountain Lion) on a 2012-era Mac Mini (Core i5 Intel CPU). In Terminal.app, enter the following command:

sudo nvram SystemAudioVolume=%80

The sudo command will ask for your login password. It needs elevated privileges to update your Mac's NVRAM settings (the Mac equivalent of a PC's BIOS). Don't be put off by the %80 value. It will indeed mute the start-up chime.

If you ever decide you want the chime back again, delete the setting from NVRAM with this command:

sudo nvram -d SystemAudioVolume