One beep during startup? (It's NOT the chime.) What does it mean?

Hey, leroydouglas ...

Thanks for the DropBox sound byte ... yes, that's it.

This occurs on my MacBook Pro 2019 (Intel) running Monterey 12.4.

• It is not this: "ref: If your Mac beeps during startup - Apple Support"

"one ping only, Vasili"

• "I suspect this is the charger registering power"

It occurs whether I'm plugged in to power or on battery

Have you seen in Apple documentation that this occurs when it sees power? (I'm assuming charger power.)

• "You can have the option turned off for start up tone."

I run with it turned off due to people sleeping in my household. It's a beep/churp, not the chime startup sound.

• "Monterey does seem to have an additional boink associated with start up— this is normal Monterey"

Is this documented somewhere? Where have you seen that as a normal Monterey startup occurrence?

My thoughts ...

• • In the the startup process, this beep occurs when the kernel is loading the foundation of Mac OS and running all of the programs that make up the operating system. It loads even more drivers than the booter process and it runs the core BSD Unix operating system.
  • When the progress bar and Apple disappear briefly and then you see them reappear quickly and continue, the kernel has then finished its job and it's handing that process over to another process called launchd.
  • So ... the beep is happening during the stage after booter, but before launchd, and thus during the kernel processing.

I've not found anyone having documented this as normal or having some meaning. I'm just trying to track it down. And BTW, it doesn't matter whether or not I have anything plugged into the audio port--it always beeps through the Mac speakers.

If nobody comes up with an answer here, I will contact Apple support and post and update here. It's got to mean something! Maybe it's just a "Hooray! The kernel scored one for the team!"

Thank you, leroydouglas , for taking time to respond! I'd appreciate any other thoughts (or corrections to my thinking) you can offer.

Ok, leroydouglas

I owe you one. Thank you, again, for your help. When I wrote, "It occurs whether I'm plugged in to power or on battery," I had that wrong. It was attached to power when I thought it was on battery. (Uh ... how I missed that?? Don't ask. I'm using a USB-C hub that supplies power.)

You were right. The startup beep is indicating the presence of a charger plugged in--the same way it beeps when the laptop is on and you plug in the charger. And perhaps this began, thinking back, when I updated to Monterey.

I did, in the process of tracking this down, learn a lot. And no, I didn't contact Apple Support--too old and stubborn, I guess.

I appreciate all your efforts and time devoted to this forum.

One further piece of information ... it does not beep if I start up in Safe Mode. So, I think it's something getting loaded that it takes issue with, that doesn't get loaded in Safe Mode.