How to keep your Mac awake while it's locked

Display sleep isn't system sleep

A Mac can be locked, have its display off, or be asleep. Only system sleep stops your work.

After you lock, the display turns off about 30 seconds later. That's display sleep, and it doesn't stop your apps. System sleep comes later, based on your energy settings. Keeping a locked Mac working just means preventing that second step.

Sources: Apple's guide to sleep and wake settings and our tests of each lock method.

Use caffeinate for one job

1. Run this in Terminal to keep the Mac awake for two hours. Keep the window open.

   caffeinate -i -t 7200

2. Press ⌃⌘Q.
3. When you're back, press ⌃C in Terminal to stop early.

From man caffeinate:

• -i prevents idle sleep. This is the flag that matters for a locked Mac.
• -s keeps the Mac from sleeping at all, but only while on power adapter.
• -d keeps the display on too. You don't need it for downloads or terminal agents.
• -t 7200 stops after 7,200 seconds (2 hours). Omit it to run until you press ⌃C.

You may also see caffeinate -dimsu recommended online. It adds -m (disk stays awake) and -u (declares the user active to turn the display on, which lasts 5 seconds unless you set -t). For a locked Mac, -i is all you need.

To run a specific command and exit when it finishes, put it after caffeinate -i, such as caffeinate -i ./long-build.sh. To check what's keeping your Mac awake at any time, run pmset -g assertions.

Or change one setting

• MacBook: System Settings › Battery › Options › "Prevent automatic sleeping on power adapter when the display is off." It only works while plugged in. On battery, use caffeinate -i.
• Desktop Mac: System Settings › Energy › "Prevent automatic sleeping when the display is off."

The display still turns off after you lock, but the Mac keeps running behind it. Read more in how to keep your Mac awake.

If you'd rather not leave the login window up

The macOS lock screen shows the login window before turning dark. You can't glance at a download or an agent from across the room, and any agent taking screenshots gets black images on the lock screen (our tests).

Dimma Screen is a menu bar app that covers every display instead. Choose Turn On and Keep Awake for 30 minutes, 1 hour, 2 hours, or 4 hours. The display stays lit and the Mac stays awake. Any key press or click asks for your 4- to 8-digit PIN, your login password, or Touch ID.

• By default the cover is a 6% tint. Your screen stays visible, but input is blocked until you enter your PIN, password, or Touch ID. To hide it, choose Solid Color or Custom Image in Settings.
• When the time is up, the overlay stays and your Mac follows its usual energy settings.
• Lock Screen When Keep Awake Ends (Settings › General › Overlay, off by default) sends the Mac to the macOS lock screen when the time is up, just like pressing ⌃⌘Q.

Limits

• Not a security lock. It's a privacy overlay. Where you need real security, press ⌃⌘Q.
• Keep Awake stops at 4 hours. For longer jobs, use caffeinate -i or caffeinate -s.
• Closing the lid still puts the Mac to sleep. Keep the lid open.
• It doesn't move the pointer or press keys. macOS keeps counting idle time.

Questions