Mac Sleep Mode Not Working - Fix Guide

• Mac won't go to sleep
• Mac wakes up randomly
• Mac won't wake from sleep (black screen)
• Sleep happens too quickly or too slowly
• MacBook sleeps when lid is closed but shouldn't

1. System Settings → Displays (or Energy Saver on older Macs)
2. Check "Turn display off after" slider
3. For MacBooks: Check settings for "On battery" and "On power adapter"

Also check: System Settings → Lock Screen for when screen locks after sleep.

1. Check What's Preventing Sleep

Open Terminal and run:

pmset -g assertions

This shows processes preventing sleep. Look for "PreventUserIdleSystemSleep".

2. Close Problem Apps

Some apps prevent sleep:

• Video players (while playing)
• Download managers
• Backup software (Time Machine)
• Apps using "caffeinate" command

3. Check Bluetooth Devices

1. System Settings → Bluetooth
2. Turn off "Allow Bluetooth devices to wake this computer"
3. Or: System Settings → Battery → Options

4. Check Network Access

1. System Settings → Battery → Options
2. Disable "Wake for network access"

Find What Woke It

Open Terminal and run:

log show --style syslog | fgrep "Wake reason"

Common wake reasons:

• EC.LidOpen — Lid was opened
• OHC/USB — USB device activity
• RTC — Scheduled wake (Power Nap, etc.)
• GLAN — Network activity

Disable Power Nap

1. System Settings → Battery
2. Click "Options"
3. Turn off "Enable Power Nap"

Disable Wake on Network

1. System Settings → Battery → Options
2. Turn off "Wake for network access"

1. Press any key or click mouse — wait 10 seconds
2. Press Power button briefly (not hold)
3. If screen stays black, force restart: hold Power for 10 seconds
4. Check display cable if using external monitor

Reset SMC (Intel Macs)

For MacBooks:

1. Shut down Mac
2. Hold Shift + Control + Option + Power for 10 seconds
3. Release all keys, press Power to turn on

Reset NVRAM

1. Shut down Mac
2. Turn on and immediately hold Option + Command + P + R
3. Hold for 20 seconds
4. Release and let Mac boot normally

To prevent sleep when lid closes (with external display):

1. Connect external display, keyboard, and mouse
2. Connect power adapter
3. Close lid — Mac should stay awake

All three must be connected for "clamshell mode" to work.

In Terminal:

sudo pmset restoredefaults

This resets all power management settings to default.