Tool · The caffeinate command (Terminal)

Why caffeinate keeps your Mac awake

caffeinate is the macOS command that keeps a Mac awake on purpose. In pmset -g assertions it appears as “caffeinate command-line tool”, and the assertion type tells you which flag was used: -i keeps the Mac awake, -d keeps the display on too, -s prevents system sleep on power. It stays until the command ends, its timeout runs out, or it’s stopped. Scripts and apps sometimes start it in the background.

Checked on macOS 27.2.1 on a MacBook Pro with Apple silicon, 11 November 2026.

What you’ll see

Check it on your Mac

Open Terminal (in Applications › Utilities) and run:

caffeinate -i -t 4 & pmset -g assertions | grep -A2 caffeinate

Real output from the Mac we checked:

   pid 53282(caffeinate): [0x0000648f000193bb] 00:00:01 PreventUserIdleSystemSleep named: "caffeinate command-line tool"
	Details: caffeinate asserting for 4 secs
	Localized=THE CAFFEINATE TOOL IS PREVENTING SLEEP.

Activity Monitor shows the same thing without Terminal: open its Energy tab and look at the Preventing Sleep column.

What to do

1. If it’s yours, go back to that Terminal window and press Control-C.
2. If you don’t know where it came from, run ps -o pid,ppid,command -p $(pgrep caffeinate) to see its full command line and its parent process.
3. To stop it, killall caffeinate. The script that started it may start it again.

See it without Terminal

SleepPilot, a menu bar app, lists every app that is keeping your Mac awake right now by name — audio through coreaudiod is shown under the app that plays it — and warns you when one holds the Mac awake for too long while nobody is using it. Each morning it can show what kept the Mac awake overnight.

Questions

Other things that keep a Mac awake

• powerd — “Prevent sleep while display is on”: normal while you use the Mac, gone when the display sleeps.
• Electron — An app built with Electron asked to stay awake; the assertion is named just “Electron”.
• All of them
• Guide: why won’t my Mac sleep?