How to keep a Mac awake until a download finishes

Does a Mac keep downloading while it is asleep?

No. A sleeping Mac does not run ordinary apps, so a browser, Steam, App Store or Terminal download stops until the Mac wakes.

Easiest way: Napless. It keeps the Mac awake until a download finishes, then lets it sleep. Allow Display to Sleep is on by default, so the screen can go dark while the download keeps going. Try Napless free for 7 days.

The only work Apple describes a Mac doing while asleep is Power Nap. On battery, Power Nap checks Mail, updates Calendar and updates other iCloud events. On a power adapter it can also download software updates and run Time Machine backups. Your files are not on that list.

What happens when the Mac wakes is up to the app and the server. Some transfers carry on, some fail, and some start over. The Apple Community thread “Computer sleeps and kills download” has 163 “me too” replies from people who lost transfers this way. The original poster fixed it with caffeinate.

Why does a Mac sleep during a download when the display is off?

A Mac goes to sleep after a stretch with no user activity, and a download does not count as user activity. Unless the downloading app holds a power assertion, macOS treats the Mac as idle.

Apple’s IOPMLib.h header in the macOS SDK describes the assertion that blocks this, PreventUserIdleSystemSleep, as preventing “the system from sleeping automatically due to a lack of user activity.” Apps have to ask for it. Many don’t.

Display sleep and system sleep are separate timers. man pmset lists displaysleep (display sleep timer) and sleep (system sleep timer) as different settings. When the display goes dark, the download is still fine. The trouble starts when the system timer fires, or, on a laptop, when the display turns off and nothing tells the Mac to stay up. Apple’s laptop option “Prevent automatic sleeping on power adapter when the display is off” exists for that case.

Closing a laptop lid or choosing Apple menu > Sleep still puts the Mac to sleep. IOPMLib.h says the system “may still sleep for lid close, Apple menu, low battery, or other sleep reasons” while that assertion is on. For lid-closed setups, read using a MacBook with the lid closed.

How do you keep the Mac awake but let the display sleep?

Hold idle system sleep without holding the display: run caffeinate -i, or turn on Apple’s “prevent automatic sleeping” option while the Mac is on power.

Mac	Setting in System Settings	When it applies
Laptop	Battery > Options > Prevent automatic sleeping on power adapter when the display is off	Only on a power adapter
Desktop	Energy > Prevent automatic sleeping when the display is off	Always

The laptop wording comes from Apple’s Battery settings page: “Prevent your Mac from sleeping when it’s plugged in and its display is off.” The desktop wording comes from Energy settings. Both are standing preferences. They stay on after the download finishes, so turn them back off if you want normal sleep.

On battery there is no System Settings switch for this. Use caffeinate -i with a time limit, plug in, or both. Apple notes that “delaying, preventing, or allowing disruption of sleep may increase power consumption.”

caffeinate -i lets the display dim and sleep as usual. Add -d only when you want the screen to stay on as well. Every way to keep a Mac awake compares the settings, the command and menu bar apps side by side.

How do you hold a download with caffeinate?

Use caffeinate -i with one of three endings: a time limit (-t), a process to wait for (-w), or the download command itself.

For a set time. -t takes seconds. Pick a time longer than the download needs:

caffeinate -i -t 7200

That holds idle sleep for two hours (7,200 seconds), then releases on its own.

Until a process exits. -w waits for a process ID and releases the assertion when that process ends. Find the ID with pgrep:

pgrep -x curl
caffeinate -i -w 10275

Use -w with a process that ends when the download ends, such as a Terminal transfer. Pointing it at a browser holds sleep until you quit the browser, not until the file lands.

Around a Terminal download. Put the command after caffeinate and the hold lasts exactly as long as the command:

caffeinate -i curl -L -O https://example.com/big-file.zip

man caffeinate says the assertions “persist for the duration of the utility’s execution.” It also says -t and -w are ignored when you give it a command, so don’t combine them with one. The caffeinate command guide covers each flag and how to stop and confirm a hold.

How do you check the download is actually holding sleep?

Run pmset -g assertions while the download runs and look for a line that names the downloading app or your caffeinate process.

pmset -g assertions

We tested this on a MacBook Pro running macOS 27.2 on 2 October 2026. A rate-limited curl download held no assertion at all. Nothing in the listing named curl. Starting caffeinate -i -w on curl’s process ID added this line:

pid 10512(caffeinate): [0x00086b670001a526] 00:00:02 PreventUserIdleSystemSleep named: "caffeinate command-line tool"
	Details: caffeinate asserting on behalf of Process ID 10275
	Created for PID: 10275.
	Localized=THE CAFFEINATE TOOL IS PREVENTING SLEEP.

When curl finished, caffeinate exited and the line was gone.

pmset -g gives a shorter check. If something holds sleep, the sleep row ends with a list such as (sleep prevented by caffeinate, powerd, coreaudiod).

Activity Monitor shows the same thing per app. Its Energy pane has a Preventing Sleep column: “Whether this app is preventing your Mac from going to sleep.” To read the full listing, see check what is holding sleep.

What about App Store, Steam, Xcode and browser downloads?

Don’t assume an app holds sleep until you’ve checked it. Look for the app in pmset -g assertions or in Activity Monitor’s Preventing Sleep column while it downloads.

We have no test results for the App Store, Steam, Xcode or any browser, so this guide doesn’t say which of them hold sleep. App versions change, and an app may hold sleep for one kind of transfer and not another. A check during your own download costs a few seconds:

1. Start the download.
2. Open Activity Monitor, click Energy, and find the app’s row.
3. If Preventing Sleep says No, or the app is missing from pmset -g assertions, add a hold yourself.
4. For an app download, run caffeinate -i -t with more seconds than the download needs. For a Terminal download, wrap the command.

If you lock the screen and walk away, the hold still applies. Lock the Mac without sleeping it covers what the lock changes and what it doesn’t.

What does Power Nap download while the Mac sleeps?

Power Nap downloads only Apple’s own items: software updates on a power adapter, plus Mail, Calendar and iCloud updates. It does not continue a browser, Steam or App Store download.

Apple’s Power Nap page lists the tasks:

Power source	What Power Nap does while the Mac sleeps
Battery	Checks for new Mail messages, updates Calendar events, updates other iCloud events
Power adapter	The above, plus downloading software updates and performing Time Machine backups

On a laptop, the setting is System Settings > Battery > Options > Enable Power Nap. On a desktop it is under Energy, and Apple says that desktop option “is only available on Intel-based Mac computers.” Power Nap also explains some of the short wakes in a sleeping Mac’s log. Why a Mac wakes from sleep by itself shows how to read them.

How does Napless handle an overnight download?

Keep Awake For and Keep Awake Until are included in the trial; after it, Napless Pro. On a Mac that installed Napless before 1.5.0, those timers stay free. Napless Pro adds watches that end when a download finishes and an Overnight Download trigger. A new install includes those watches for 7 days.

Pick the Download preset at the top of Keep Awake For for a one-click hold, or choose Keep Awake For and pick a duration longer than the download. The presets run from 5 minutes to 5 hours, and Custom Duration goes up to 24 hours. Or choose Keep Awake Until > A Specific Time…. The time left shows in the menu bar. Allow Display to Sleep lets the screen go dark while the system stays up. Try Napless free for 7 days on macOS 13 or later, on Apple silicon or Intel.

Two safety stops matter on an unattended night. Stop keeping your Mac awake if it gets too hot is on by default. Stop keeping your Mac awake when battery is low is off by default and stops at 20% unless you change it. See safety stops.

Napless Pro adds the download-specific parts, as described in Napless Help:

• While a Download Is in Progress. An automatic condition: while the Downloads folder contains a Safari .download, Chrome .crdownload, Firefox .part or generic .partial/.opdownload file that has been written to within the last two minutes, the Mac stays awake (Help).
• Watch a download. Drag the file or folder onto the menu bar icon, or choose Keep Awake Until > A Download Finishes…. The Mac stays awake until the download finishes.
• Overnight Download. This Quick Setup under automatic Keep Awake “turns on network activity while on power”. The Mac stays awake while the network is busy and a power adapter is connected.
• Keep Mac Awake Until Download Finishes, a Shortcuts action.

Napless Pro automatic keep-awake for downloads is $8 for the first 50 licenses, then $24, one time, for up to 3 Macs. A timer or caffeinate -i -t still works without it. To hold sleep until the download finishes, Try Napless free for 7 days.

Questions

Does a Mac keep downloading while it is asleep?

Not for ordinary apps. Power Nap runs a short list of Apple tasks during sleep, such as Mail, Calendar and iCloud updates, plus software updates and Time Machine on a power adapter. A browser or Steam download is not on that list.

Which caffeinate command keeps a Mac awake for a download?

Run caffeinate -i -t 7200 for two hours, caffeinate -i -w PID to hold until a process exits, or caffeinate -i curl -O URL to hold for exactly as long as a Terminal download runs.

Can the display turn off while the download keeps going?

Yes. caffeinate -i blocks idle system sleep only, so the display can still sleep. On a laptop, the System Settings option for this works only on a power adapter.

Do downloads keep a Mac awake on their own?

Not reliably. A download is not user activity, and an app has to hold a power assertion to block idle sleep. A curl download tested for this guide held none. Check with pmset -g assertions.