Guide · macOS

How to lock your Mac without turning off the screen

macOS has no setting for this. When you lock your Mac, it assumes you’ve left, and the display usually goes dark within seconds. The free thing to try is caffeinate in Terminal: the screen may stay on, showing the login window. If you want your desktop to stay visible, so it looks like you’ll be right back, use a cover app like Dimma Screen.

Why the screen goes dark when you lock

Locking tells macOS you’re no longer using the Mac. One answer on Reddit puts it plainly:

“It is assumed that when you lock the screen, you are no longer using the computer and you do not need the screen on.”r/mac, 2023

People have asked about this for more than ten years. Many report that the display turns off a few seconds to half a minute after they lock, whatever the Lock Screen settings say. It helps to keep three things apart:

Term	What it does	How it starts
Lock screen	Shows the login window. You need your password or Touch ID to get back in.	⌃⌘Q, Apple menu › Lock Screen, Touch ID, or a hot corner
Screen saver	Plays after a period of inactivity. It locks the Mac only if a password is required after it begins.	After the time you set, or from a hot corner
Display off	Turns the display off. Your apps keep running unless the Mac also sleeps.	After the “Turn display off” time in System Settings › Lock Screen

Your options, side by side

Method	The display	What people see	The catch
Lock Screen (⌃⌘Q)	Usually goes dark within seconds	The login window	There’s no setting for how long the display stays on
`caffeinate -d`, then lock	Often stays on	The login window	Needs Terminal. Results vary by Mac and macOS version
Hot corner screen saver with a password	On until your “Turn display off” time	The screen saver	A screen saver says you’ve stepped away
Dimma Screen	On for 30 minutes to 4 hours, your choice	Your desktop under a faint tint	A privacy overlay, not a security lock. macOS 26 or later

Try caffeinate first

caffeinate comes with macOS. The -d option keeps the display from sleeping, -i keeps the Mac from idle sleep, and -t sets a time limit in seconds.

Open Terminal.
Run this to keep the display and the Mac awake for one hour. Leave the window open.
```
caffeinate -d -i -t 3600
```
Press ⌃⌘Q to lock.
To stop early, go back to Terminal and press ⌃C.

Try it once before you rely on it. If the display still goes dark on your Mac, macOS has no other built-in switch for it.

Keep your Mac awake while it’s locked

Locking doesn’t quit your apps. Sleep pauses them. Downloads, builds, and syncs keep going while the Mac is locked, as long as it stays awake.

caffeinate -i keeps the Mac from idle sleep until you stop it.
caffeinate -s keeps the Mac from sleeping at all, but only on power adapter.

External displays go dark too

Locking turns off external displays the same way. Some monitors also have their own standby timer. If a monitor goes dark while the Mac is still awake, check the monitor’s own menu.

When you don’t want it to look like you’ve left

The login window tells everyone walking by that you’re gone. A dark screen does too.

Dimma Screen is a menu bar app for macOS 26. Step away and it covers every display with a tint you can barely see. Your desktop stays lit and keeps moving, so it looks like you’ll be right back. Touch a key or the mouse, and it asks for your PIN.

Lock and Keep Awake for 30 minutes, 1 hour, 2 hours, or 4 hours. The display stays lit and your Mac stays awake, so downloads and builds keep running.
Locks on its own after 5, 10, 20, or 30 minutes or an hour without input. Or set your own keyboard shortcut.
Away Note puts one line on every display, like “Back in 5,” with the time you’ll be back.
Unlock with your 4- to 8-digit PIN, your login password, or Touch ID.

See how it works Download

macOS 26 Tahoe or later · Apple silicon · Version 1.0 is in final testing

When you need real security

A cover keeps coworkers walking past and the person in the next seat off your screen. It isn’t a security lock. When you leave your Mac somewhere you don’t trust, press ⌃⌘Q. In Dimma Screen you can also choose Lock, Then Lock Screen: when the time runs out, it hands over to the macOS lock screen.

Questions

Why does my Mac’s screen go dark right after I lock it?

macOS treats locking as leaving, so it turns the display off soon after the login window appears. Many people report that this happens even when the Lock Screen settings say otherwise. There’s no built-in switch to change it.

Does locking my Mac stop downloads?

No. Locking doesn’t quit your apps. Sleep pauses them. Keep the Mac from sleeping, for example with caffeinate -i, and downloads keep going while it’s locked.

Can the lock screen show my desktop instead of the login window?

Not with the built-in settings. The lock screen always shows the login window. A cover app like Dimma Screen leaves your desktop visible under a faint tint and asks for a PIN instead.

Is it safe to leave the screen on?

A screen that shows the login window is still locked, so keeping it on is fine. A cover app keeps people nearby off your screen, but it isn’t a security lock. Where you need real security, press ⌃⌘Q.