I'm running an MacBook Pro Retina (Mid 2014) with macOS High Sierra (10.13.3).

Coincidentally, I found the key combination Control ⌃+Option ⌥+Shift ⇧+Power button that immediately turns the MacBook off. As soon as I press the buttons, the screen is black and the computer is off. It's like a kill switch.

What is that shortcut for and how is it called? Does it hurt my computer?

EDIT: Maybe it is related to the SMC Reset? https://support.apple.com/en-us/HT201295


Apple's list of common Mac keyboard shortcuts does not include this exact keyboard combination. You're presumably just activating the Ctrl-Shift-Power shortcut instead, which just turns off your display. This, of course, will do no harm to your computer.

  • This doesn't make much sense. If I press Command-Shift-C, it does not trigger Copy, even though Command-C does. Adding extra keys to a shortcut makes it a different shortcut, one which may or may not be set, but it doesn't find a "close" shortcut and trigger that one instead. – tubedogg Jan 31 '18 at 1:28
  • No the MacBook is definitely turned off. – MrMartiniMo Jan 31 '18 at 7:39
  • If I press the power button afterwards, the MacBook boots up normally. – MrMartiniMo Jan 31 '18 at 7:49
  • @tubedogg the OP could have been slower with the option key.... – Solar Mike Jan 31 '18 at 8:16

According to the apple support: This key combination resets the SMC (System Management Controller). The SMC takes control of the battery. Once the controller has been reset, the power supply is cut off. It is not recommended to do this while the Mac is turned on.

  • the commands for resetting the smc vary between some of the models - is this a universal command or just for one model - yours? – Solar Mike Jan 31 '18 at 10:24
  • This keyboard shortcut is for MacBooks with nonremovable batteries only. – MrMartiniMo Jan 31 '18 at 10:27

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .