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Fix a Mac that will not sleep

We'll check Energy Saver settings, prevent sleep blockers, and isolate the cause—app, setting, or hardware—or tell you when to call a pro.

Troubleshooting · Home maintenance
5–15 min
Step 1 of 5

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Steps

Goal: Rule out sleep timers and preventing-sleep apps, then isolate peripherals or hardware.

  • Check Energy Saver or Battery settings. Set display sleep to 5–15 minutes.
  • Good: Timers set. Proceed to Check preventing-sleep apps.
  • Bad: Timers at Never—set them first.

Check Energy Saver

Goal: Confirm sleep timers are configured.

  • System Settings, Battery (or Energy Saver). Set “Turn display off after” to 5–15 minutes. Confirm “Put hard disks to sleep” is on if shown.
  • Good: Sleep timers set. Proceed to Check preventing-sleep apps.
  • Bad: If the Mac still does not sleep, check for apps preventing sleep.

Check preventing-sleep apps

Goal: Find apps that block sleep.

  • Run in Terminal: pmset -g assertions. Look for “PreventSystemSleep” or “PreventUserIdleSystemSleep.” Quit the app holding the assertion.
  • Good: No blocking apps. Proceed to Verification.
  • Bad: Quit the app and retest. If the Mac still does not sleep, disconnect peripherals and disable wake-on-LAN.

When to get help

Call Apple or a technician if:

  • The Mac never sleeps after closing the lid.
  • Sleep settings and app checks do not help.
  • SMC reset did not fix lid-close sleep.

Verification

  • Display turns off after the set time.
  • Mac sleeps when the lid is closed (laptops).
  • No unexpected wake from sleep.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Energy Saver Set display and computer sleep timers.
  2. Preventing-sleep apps Check pmset -g assertions; quit blocking apps.
  3. Peripherals and wake Disconnect external displays; disable wake-on-LAN and Power Nap.
  4. Call a pro Lid does not trigger sleep; SMC reset did not help.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Mac model and macOS version:
  • Sleep timers: display and computer
  • pmset -g assertions output (blocking processes):
  • Steps already tried:

Are sleep timers set in Energy Saver?

Sleep set to Never is a common cause.

System Settings, Battery. Set "Turn display off after" to 5–15 min. Good: timers set—check for preventing-sleep apps. Bad: timers at Never—set them first.

Yes No

You can change your answer later.

Set sleep timers

System Settings, Battery. Set display sleep to 5–15 min. Disable wake-on-LAN and Power Nap if needed.

Done

Is an app preventing sleep?

Run pmset -g assertions to find blockers.

Terminal: pmset -g assertions. Look for PreventSystemSleep. Quit the app holding it. Good: no blockers—disconnect peripherals. Bad: app identified—quit it.

Yes No

You can change your answer later.

Disconnect peripherals and disable wake

Unplug external displays and USB devices. Disable wake-on-LAN and Power Nap. Reset SMC if lid does not trigger sleep.

Done

Mac sleeps

The Mac sleeps when the timer expires or the lid is closed. You are done.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why would a Mac not sleep?
Sleep timers set to Never, an app preventing sleep, external display, wake-on-LAN, or Power Nap. Check Energy Saver and Activity Monitor first.
Can I fix a Mac that will not sleep myself?
Yes. Set sleep timers, quit apps that prevent sleep, disconnect external displays, disable wake-on-LAN. If the lid does not trigger sleep, reset SMC.
When should I call a technician for a Mac that will not sleep?
If the Mac never sleeps after closing the lid, or sleep settings and app checks do not help. Hardware or sensor failure may need repair.

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