Find the app that stops your Mac going to sleep

Why it happens

Apps can ask your Mac to stay awake while they work, for example while a video plays, a file downloads or a backup runs. Most let go when they finish. Some forget, or keep a window open in the background, and your Mac stays awake with nothing obvious on screen.

How to fix it

1. Press Command-Space, type Activity Monitor and press Return. You can also find it in the Utilities folder inside Applications.

2. Click Energy at the top of the window. Find the Preventing Sleep column and click its heading so the apps marked Yes move to the top.

   Activity Monitor›Energy

3. Note the names marked Yes. A browser tab playing video, a music app or a download manager are the usual ones.

4. Switch to that app, save anything you're working on and press Command-Q to quit it. If it won't quit, select it in Activity Monitor, click the X button at the top of the window and choose Quit.

5. Check that Preventing Sleep now says No for every app. Then leave the Mac untouched for longer than the Turn display off time in Lock Screen. It should go to sleep on its own.

Still not fixed?

1. Closing the lid while a MacBook is plugged in and connected to an external display keeps it running on the big screen. That's normal. Unplug the display if you want it to sleep.

2. On a MacBook, check that your Mac isn't set to stay awake on power. In Battery, click Options… and turn off Prevent automatic sleeping on power adapter when the display is off.

   Battery›Options…›Prevent automatic sleeping on power adapter when the display is off

3. Look at your screen timers too. In Lock Screen, pick a time for Turn display off on battery when inactive and the matching power adapter option, so the screen goes dark first.

   Lock Screen

4. Restart the Mac from the Apple menu. That clears any app or background task that got stuck holding the Mac awake.

5. If nothing shows Yes in Preventing Sleep and the Mac still won't sleep after a restart and the latest macOS update, contact Apple Support so they can check it with you.