How to Keep a Mac from Sleeping (macOS Settings and Terminal)
macOS has one advantage over Windows here: a keep-awake tool is already installed. It is called caffeinate, it lives in Terminal, it needs no download, and it does exactly one job well.
This guide covers the Settings route, the Terminal route, and what to do on a Mac managed by an employer.
Route 1: System Settings
Apple has reorganised these panels several times, so the exact wording depends on your macOS version. On recent releases:
- Open System Settings from the Apple menu.
- Go to Lock Screen. This holds "Turn display off on battery when inactive", "Turn display off on power adapter when inactive", and "Require password after screen saver begins or display is turned off".
- Set the display-off values to Never for power adapter, and leave a sensible value on battery.
- Go to Battery (laptops) or Energy Saver (desktops) and click Options.
- Enable Prevent automatic sleeping on power adapter when the display is off if you want background work to continue with the screen dark.
That last option is the one worth understanding. It separates two ideas that people usually conflate: the display sleeping, and the machine sleeping. With it enabled, your Mac can go dark while a download, backup or render continues at full speed - which is usually what you actually wanted.
Route 2: caffeinate in Terminal
Open Terminal (Applications → Utilities, or press Command+Space and type Terminal) and use one of these:
| Command | What it does |
|---|---|
caffeinate | Prevents system idle sleep. Display may still turn off. |
caffeinate -d | Prevents the display sleeping. This is the one most people want. |
caffeinate -i | Prevents idle sleep of the system. |
caffeinate -s | Prevents sleep while on AC power. |
caffeinate -d -t 7200 | Keeps the display awake for exactly 7200 seconds (2 hours), then stops. |
caffeinate -d -w 4821 | Stays awake until process ID 4821 exits. |
caffeinate -i make build | Runs a command and keeps the Mac awake only until that command finishes. |
To stop it, press Ctrl+C in the Terminal window, or just close the window. There is nothing to uninstall and nothing left running afterwards.
The best form is the last one in the table. caffeinate -i ./long-script.sh keeps the machine awake for exactly as long as the job takes and not a second more - no remembering to turn it off, no flat battery in the morning.
Route 3: Hot corners for the opposite problem
While you are in the settings, it is worth knowing about the reverse trap. System Settings → Desktop & Dock → Hot Corners lets you assign screen corners to actions, and one of the defaults on some setups puts the display to sleep when the pointer reaches a corner. If your Mac blanks the moment you flick the mouse to a corner, that is why.
Route 4: Amphetamine and other apps
Amphetamine, from the Mac App Store, is the best-known graphical option. It adds triggers - keep awake while a specific app is running, while a drive is mounted, while the battery is above a threshold - which caffeinate cannot do without scripting. It is free and well maintained.
If caffeinate covers your need, though, there is no reason to install anything. Fewer background utilities is generally the better outcome.
On a managed Mac
If your Mac is enrolled in an MDM system, the sleep and lock settings may be enforced by a configuration profile. You will see options greyed out, and you can confirm it under System Settings → Privacy & Security → Profiles (visible only if profiles are installed).
What still tends to work:
caffeinate- it is part of macOS and needs no admin rights, though a profile can still force a screen lock independently.- A browser-based jiggler - changes nothing on the machine at all. Note that this needs an external optical mouse; it cannot work with the built-in trackpad.
- Asking IT - most organisations have a sanctioned approach for presentation and lab machines.
What will not work: fighting the configuration profile. If the password-after-lock delay is set to zero by policy, the screen will lock the moment the display turns off, and preventing display sleep is the only way around it.
Checking what is keeping your Mac awake
The inverse question - why will it not sleep - has a good answer too. In Terminal, run:
pmset -g assertions
This lists every process currently asserting that the system or display must stay awake, with the reason. A video call app, a media player, or a forgotten caffeinate will show up here immediately.
Related: pmset -g shows your current power settings, and pmset -g log | grep -e "Sleep" -e "Wake" gives a history of sleep and wake events with their causes.
Quick reference
- Display keeps turning off → Lock Screen settings, or
caffeinate -d. - Machine sleeps during a long job → Battery → Options → prevent sleeping when display is off, or
caffeinate -i. - Password prompt appears immediately → "Require password after..." setting.
- Blanks when the pointer hits a corner → Hot Corners.
- Everything greyed out → MDM profile; use
caffeinateor a jiggler.