Why Is My Mac Not Going to Sleep? Find the Cause in One Command

Your Mac is not going to sleep because an app or a system service is holding a sleep assertion, a request that tells macOS to stay awake. To see which one, open Terminal and run pmset -g. The sleep line ends with "sleep prevented by" and a list of process names. The usual ones are coreaudiod (something is playing audio, often a browser tab or a video call), a browser, Zoom or Teams during a call, sharingd (Handoff or AirDrop), Time Machine, and keep-awake apps such as Amphetamine or caffeinate. Close the app, stop the audio, or turn off the setting, and the Mac sleeps on its normal timer.

If you keep your Mac awake only so Slack stays green, you can let it sleep. With nobody touching it, an awake Mac still shows you away in Slack after 10 minutes.

Find what is keeping your Mac awake

Run this in Terminal. It needs no admin password:

# the sleep line lists every process that is blocking sleep right now
pmset -g | grep -i sleep

This is real output from a MacBook that refused to sleep:

 sleep                1 (sleep prevented by powerd, coreaudiod, coreaudiod, sharingd, Amphetamine, Helium)
 displaysleep         10 (display sleep prevented by Amphetamine)

Two apps are playing audio (coreaudiod appears once per audio stream), Handoff is active (sharingd), Amphetamine is holding the Mac and the display awake, and a browser (Helium) holds its own assertion. powerd with "Prevent sleep while display is on" is normal and goes away when the display sleeps.

For details, list the assertions with their names and how long each has been held:

pmset -g assertions

pid 404(coreaudiod): [...] 00:26:31 PreventUserIdleSystemSleep named: "com.apple.audio...preventuseridlesleep"
    Created for PID: 87244.
pid 660(sharingd): [...] 00:09:22 PreventUserIdleSystemSleep named: "Handoff"
pid 847(Amphetamine): [...] 242:29:48 PreventUserIdleSystemSleep named: "Amphetamine (Single-Use - System)"
pid 42972(Helium): [...] 00:02:51 NoIdleSleepAssertion named: "Playing audio"

The Created for PID line under coreaudiod names the app that owns the audio. Look it up with ps -p 87244 -o comm=. Without Terminal, open Activity Monitor, choose the Energy tab, and look at the Preventing Sleep column.

The usual causes, and the fix for each

A keep-awake command you forgot is easy to miss. caffeinate started in a Terminal tab keeps the Mac awake until that tab closes; caffeinate on Mac covers its flags. Menu bar apps such as Amphetamine, compared in the best apps to keep a Mac awake, can have triggers that turn them on by themselves, for example while a certain app runs or while on power.

Settings that keep a Mac awake on purpose

If pmset shows nothing unusual, check the settings. On a MacBook, open System Settings > Battery > Options; on a desktop Mac, System Settings > Energy:

• • Prevent automatic sleeping on power adapter when the display is off. When on, the Mac never sleeps while plugged in. Turn it off.
• • Wake for network access. Lets the Mac wake for file sharing, Find My and remote access. Set it to Only on power adapter or Never.
• • Enable Power Nap. Lets the Mac wake briefly for mail and backups while asleep.

Then check System Settings > Lock Screen: Turn display off when inactive controls when the display sleeps, and the Mac follows a few minutes later. On the Terminal side, pmset -g shows the same values: sleep 0 means system sleep is off, and displaysleep is the display timer in minutes.

A sleeping Mac keeps waking up

A Mac that goes to sleep and then wakes, often at night, logs every wake with a reason:

# the last 20 wakes, with what caused them
pmset -g log | grep -E "DarkWake from|Wake from|DarkWake to FullWake" | tail -20

A "DarkWake" is a short wake with the display off, for maintenance or network work. A real wake reads "DarkWake to FullWake ... due to UserActivity". Reasons you will see:

• wifi or bt: a network or Bluetooth device. Turn off Wake for network access, and disconnect Bluetooth devices you do not use.

• USB-C_plug or USB: a charger, dock or USB device was plugged in or changed state.

• Maintenance or DHCP lease renewal: normal short DarkWakes; they do not turn the display on.

• A calendar or app alarm: pmset -g sched lists scheduled wakes.

Still not sleeping

Restart the Mac. It clears assertions left behind by apps that crashed.

Disconnect external displays, docks and USB devices, then test again. Some docks and USB audio interfaces hold the Mac awake.

On a work Mac, check for a device-management profile in System Settings > General > Device Management. Company policy can set sleep and lock times.

For the opposite problem, keeping a Mac awake on purpose, see how to keep a Mac screen from locking. If your Mac sleeps too soon instead, see Mac keeps going to sleep.

FAQ

What is keeping my Mac awake? Run pmset -g in Terminal and read the "sleep prevented by" list, or check the Preventing Sleep column in Activity Monitor's Energy tab.

Why does my Mac not sleep when a video is paused? Some players and browser tabs keep the audio stream open while paused, so coreaudiod holds an assertion. Close the tab or quit the player.

Does a mouse jiggler stop my Mac from sleeping? Yes. Any input resets the idle timer, so a jiggler or a jiggler app keeps the Mac awake while it runs.