<<< MacOS 10.15 Catalina
Turn Off Auto Boot
One of the more annoying aspects of my new MacBook Pro 16", running Catalina is the auto boot feature which means my laptop always boots when I open the lidand the biggest issue for me is that I have no way of knowing if my laptop is turned off before I put it away. Previously I used to make sure that the forcefeedback on the touch bar was not active and then I know it was safe to close the lid, but now if I do that it just boots up again.
I have also noticed that I often take my laptop out of my laptop bag and discover the batter at 90% or lower, which I put down to it being hibernated ratherthan turned off and as pressing the power button is no big deal to me I have disabled the feature.
The new MacBook Pro introduces a tweaked boot process where the machine automatically starts up when you open its lid or connect it to power, and to avoidforcing users to listen to the startup chime every time they open the lid, Apple’s also decided to disable the boot chime on the new notebook by default,this can also be easily re-enable.
Unfortunately, Apple does not provide user-facing switches in System Preferences to control the new boot on power and boot on lid capability. But, with alittle help from Terminal you can manually stop the MacBook Pro's from automatically powering on when you lift the lid or connect it to a power adapter or anexternal display.
Disable Auto Boot:
Note: This is a permanent change in you non-volatile memory
sudo nvram AutoBoot=%00
Enable Auto Boot:
Note: This is a permanent change in you non-volatile memory
sudo nvram AutoBoot=%03
Disable Boot Sound:
Note: This is a permanent change in you non-volatile memory
sudo nvram BootAudio=%00
Enable Boot Sound:
Note: This is a permanent change in you non-volatile memory
sudo nvram BootAudio=%01