macOS Mute OSX startup sound permanently without a prefpane

[Udi]

Is this possible?
The only thing that has been successful has been Arcana's StartupSound.prefpane, but I'd like to implement a solution that does not require extra software. I am however interested in what exactly that prefpane does, it must do something more than what I describe below.

I've tried the login/logout hook method through Terminal, which works for one boot, sometimes two, and then stops working. Code here if anyone can spot issues.

I've tried to figure out why it stops working. I've set chmod 777 on the two files, and their new permissions have stayed put. However the hooks just seem to stop working after one shutdown/startup cycle.

The other weird thing I found was, if I only set the "logout" hook (and restart a couple times so it fails to work as described above), the volume is still muted AFTER boot, which tells me that the hook is not actually working when it should (works on login rather than logout, which is useless).

Could the problem be that I'm using ctrl+alt+cmd+eject to shutdown? It is still a proper shutdown process - just ignores applications asking questions. FWIW, the Arcana prefpane works perfectly no matter how I shut down. I want to replicate its functionality with my own script.

Thanks

 

[dan1eln1el5en]

since some years ago there is a software update in the Macs efi that allows you to press mute just before or at chime startup and the computer will remain silent.

I've had success with this on 2nd ten Macbook Air, 1st ten Mac Pro and I kinda think it worked on my current Mac mini, until I reset the thing a few weeks back. (now the chime is back)

 

[Udi]

Thanks but I'm really looking to write some code to disable it, perhaps via a logout hook. I found this method quite unreliable though as sometimes the hook does not work, perhaps someone can explain how the Arcana prefpane does it - since it's the only successful solution I've found.

I've gone back to it for now, but would prefer a hand-coded solution without the prefpane.

 

[ArtOfWarfare]

Thanks but I'm really looking to write some code to disable it, perhaps via a logout hook. I found this method quite unreliable though as sometimes the hook does not work, perhaps someone can explain how the Arcana prefpane does it - since it's the only successful solution I've found.

I've gone back to it for now, but would prefer a hand-coded solution without the prefpane.

You could just email the developer and ask how it works. Maybe just ask to see a copy of the source code, since it's freeware anyways.

Also, you could try using Hopper Decompiler on it to see how it works (not sure how that works with prefpanes.)