Whenever I want to download something which is over a gigabyte, I leave my computer, so the download could happen smooth and fast, but that's not to be, when my computer goes to sleep, and the Wi-Fi turns off.

5 Answers 5


In OS X 10.8 Apple introduced an "aggressive system sleep" to aid laptop power consumption and battery life. This means that applications have to tell the OS when they don't want it to sleep because they are, say, working on a long task that doesn't require user input.

If you're using an application that hasn't been updated to issue these requests (known as power assertions) you can issue them yourself from the command line using the caffeinate command. To do this open Terminal.app and enter,


The machine will stay awake until you abort the command with CTL+c. To allow the screen to sleep as per your normal System Settings use,

caffeinate -s

To make the power assertion expire after a fixed number of seconds (e.g., 1 hour = 3600 seconds) use,

caffeinate -t 3600

Once that expires your normal sleep settings will resume.

  • Nice clean approach, claps!
    – wukong
    Aug 19, 2019 at 13:05

When your mac goes into sleep mode, your hardware will goes to sleep mode. Hence, it is not possible for you to keep your wifi on while in sleep mode.

To workaround, you may:

  1. Disable sleep mode [1]
  2. Set your display to sleep manually or automatically after certain minutes [2]

There is a nosleep Mac OS X kernel extension.



open terminal.app and type:

sudo systemsetup -setcomputersleep Never
sudo pmset -a standby 0

also try the freeware "insomniaX"

  • 2
    A link to the software and its main features would be welcomed as well as an explanation of what the commands you listed do!
    – Zain Patel
    Jun 28, 2015 at 19:43

"InsomniaX is a small utility that acts as a wrapper to the Insomnia kernel extension. InsomniaX disables either lid and/or idle sleep on your MacBook - any MacBook - allowing you to play music through speakers even while it's closed! or simply just to quickly stop the system from going to sleep on idle"


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