I have a MacBook Air that the lid I left open. The screen was still on when I left it. In System Preferences, I set it to turn off the display and sleep after 10 minutes. But it didn't turn off. I know that because the next morning, all the battery ran out. Why didn't it sleep like the MacBook Air is supposed to?

EDIT: This is the result of the pmset- g command in Terminal.

Active Profiles: 
Battery Power -1 
AC Power 2* 

Currently in use: 

standbydelay 4200 

standby 1 

womp 1 

halfdim 1 

hibernatefile /var/vm/sleepimage 

darkwakes 1 

networkoversleep 0 

disksleep 10 

sleep 10 (sleep prevented by coreaudiod) 

hibernatemode 3 

ttyskeepawake 1 

displaysleep 10 

acwake 0 

lidwake 1 –
  • was the lid open or lid closed ? there is a sensor in the lid that might be broken.
    – Ruskes
    Commented Jun 30, 2015 at 16:36
  • 1
    With lid open any app you have could have keep it awake. Was it connected to Internet with some streaming page ? So how does it know you want it to sleep ?
    – Ruskes
    Commented Jun 30, 2015 at 16:38
  • 1
    If you are handy with your Mac, open the Terminal app and type "pmset -g" then copy and paste the results here.
    – Ruskes
    Commented Jun 30, 2015 at 16:52
  • 1
    there you go, now you know :) it was playing or trying to play something !
    – Ruskes
    Commented Jun 30, 2015 at 17:22
  • 1
    "Coreaudio" is your audio device. Something was using it. Did you had any music running?
    – Ruskes
    Commented Jun 30, 2015 at 18:10

1 Answer 1


If you run following command in the Terminal app it will show you what keep it from sleeping.

pmset -g assertions

Then based on the result you can take a action.

Here is a example:

pid 251(coreaudiod): [0x0000000100000d01] 00:17:27 NoIdleSleepAssertion named: "com.apple.audio.'AppleHDAEngineOutput:1B,0,1,1:0'.noidlesleep" 
pid 251(coreaudiod): [0x0000000100000929] 01:11:47 NoIdleSleepAssertion named: "com.apple.audio.'BoomEngine:0'.noidlesleep"

In this case it was the "BoomEngine app" preventing the sleep.

In your case:

You have the "magicwake" which is keeping it from sleeping.

That could be a Bluetoot coming from headset or external keyboard(track pad), or the battery is low.

It could be also a app that you installed that would wake up on network access.

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