On a touchbar Macbook Pro,
1) Set volume to average level
2) Plug in power cord
Sound is heard. Unplug power
3) Raise volume level
4) Plug in power cord
Sound is heard at higher level, indicating that system volume effects this event. Unplug power
5) Mute system volume
6) Plug in power cord
Sound is heard at same volume as step 4
System mute should mute ALL sounds.
Mute requires the OS to be running which it isn't when you connect power. I doubt that Mute is saved along with the default sound level in the pram. You can check the pram by zapping it: Resetting your Mac's PRAM and NVRAM. Are you muting sound via the keyboard function key at the top of the keyboard? Does your model emit the startup chime?
I think maybe you’re not understanding the issue. Maybe I’m not describing it very well. :)
If I mute my laptop, I expect all sounds to be muted. The laptop shouldn’t decide to make a noise when I plug in its power connector if I have specifically muted the system.
For instance, if I have my volume turned up quite loud during the day, but then hit the mute button in the evening, I shouldn’t expect to get blasted by the power connect sound.
The machine/OS is running at the time. I'm using the mute soft button on the touchbar.
BTW, touchbar Macbooks no longer have a startup sound.
Interestingly, you can actually see the volume icon on the touchbar briefly UNmute itself when the power cord is connected. It's like Apple did this on purpose for some reason.
Possibly because of the eliminated startup chime.
Open Sound preferences > Sound Effects > configure options and settings.
Yeah ... I'm not finding the setting for "System mute only mutes certain sounds." 😉
Please try it on your nearest touchbar Macbook Pro, let me know if it does the same thing.
There are only two options. Disable both. Then try one then the other to see which suits you.
I can't explain this any better. I appreciate your attempts to offer workarounds, but this is a bug, not a configuration issue.
System mute does not mute power connect sound
