How to keep your Mac awake while a big download finishes

Why downloads stop overnight

When the Mac sleeps, apps stop running, and so does the download. Whether it picks up again after the Mac wakes depends on the app and the server: some resume, some fail and have to start over.

Some apps tell macOS not to sleep while they download. On our test Mac, Google Chrome held an assertion called “Download in progress” while it downloaded. The power log records it when it’s released, with how long it was held (shortened):

pmset -g log | grep "Download in progress"

2026-11-11 12:18:41 +0200 Assertions           PID 8107(Google Chrome) Released NoIdleSleepAssertion "Download in progress" 00:00:13  […]
2026-11-11 12:18:47 +0200 Assertions           PID 8413(Google Chrome) Released NoIdleSleepAssertion "Download in progress" 00:00:10  […]
2026-11-11 12:18:55 +0200 Assertions           PID 7832(Google Chrome) Released NoIdleSleepAssertion "Download in progress" 00:00:12  […]

To see whether your browser or download app does the same, start a download and run pmset -g assertions. If the app isn’t listed, nothing stops the Mac from sleeping halfway. Background transfers by macOS and some apps go through nsurlsessiond, which on our Mac took short assertions of its own while they ran.

Keep it awake with caffeinate

1. 1Connect a MacBook to power so the battery doesn’t run out during the night.
2. 2Open Terminal from Applications › Utilities.
3. 3Type caffeinate -i -t 14400 and press Return. That keeps the Mac awake for four hours (14,400 seconds); pick more than you think the download needs.
4. 4The display turns off as usual, but the Mac stays awake and the download keeps going. Press Control-C when it’s done to let the Mac sleep sooner.

caffeinate -i -t 14400

If you download from Terminal, put caffeinate in front and the Mac stays awake exactly as long as the download runs (replace the address with yours):

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

For a Mac that’s always downloading or sharing, there’s a setting instead: System Settings › Battery › Options › Prevent automatic sleeping on power adapter when the display is off on a laptop, or Prevent automatic sleeping when the display is off in Energy on a desktop. It stays on until you turn it off.

Is the download finished?

Browsers write to a temporary file and rename it when the download is complete. While you see one of these in Downloads, it isn’t done:

To list them from Terminal:

find ~/Downloads -maxdepth 1 \( -name "*.crdownload" -o -name "*.download" -o -name "*.part" \)

Some apps write straight to the final file name. Then the only sign is that the file is still getting bigger: run ls -l ~/Downloads a minute apart and compare the sizes.

Until the download is done: SleepPilot

SleepPilot (Mac App Store) has an Until done… option in its menu bar panel that lists files still downloading into your Downloads folder: browser partial files, or a file that’s still growing. Pick one and SleepPilot keeps the Mac awake until it’s complete (it counts a file as finished after a minute without changes), then lets the Mac sleep as usual and sends a notification. It watches only the Downloads folder in your home folder.