How to find what is keeping your Mac awake

Start with the sessions you control

When your Mac stays awake unexpectedly, first check whether you left an awake utility active. Review Mouse Jiggler’s main switch, a scheduled session, and any Terminal window running caffeinate. An unfinished export or another app may also have a reason to keep the system active.

Decide what you are diagnosing: a screen that stays illuminated, a computer that does not enter idle sleep, or a computer that wakes again later. A single setting change may not explain all three. Our sleep and locking guide separates those states.

Look in Activity Monitor

1. Open Activity Monitor from Spotlight or Applications → Utilities.
2. Select the Energy tab.
3. Look for the Preventing Sleep column.
4. If needed, use View → Columns to show it.
5. Note the names of apps that are currently preventing sleep.

Energy Impact is a relative measure of current energy use, not a remaining-battery percentage. A busy process and a sleep-prevention request answer different questions, so inspect the appropriate column.

The view is a snapshot. A request may disappear when playback, a transfer, or another task ends. Record what the app was doing when you checked.

Inspect power assertions in Terminal

For a more detailed read-only view, open Terminal and enter:

pmset -g assertions

This reports power assertions: requests that can prevent system or display sleep. The output can include a summary and the processes holding requests. It does not change your power settings.

For example, a caffeinate session may appear while it is active. End your own session with Control-C in its original Terminal window, then run the command again and compare. Read the installed manual with man pmset for details specific to your Mac.

Change one thing and compare

Use a small before-and-after check instead of quitting everything at once:

1. Save the names of relevant apps and note the time.
2. Finish or stop one known task using its normal controls.
3. Refresh the Activity Monitor view or rerun the Terminal command.
4. Wait through your configured idle timeout without touching the input devices.
5. Check whether the symptom changed.

Do not assume a process with an unfamiliar name is faulty. It may be a normal system component. If you cannot identify it, investigate its role before attempting to stop it.

Understand what the check does not prove

A utility that simulates input does not necessarily appear as its own named sleep assertion. Likewise, a snapshot without an obvious request is not a complete history of wakes, accessories, or network activity.

If Mouse Jiggler is involved, temporarily switch its main control off and repeat your test. If the Mac still behaves unexpectedly, record the power source, attached devices, timeout, and the exact symptom. That gives support more useful evidence than a screenshot of a single process name.

For a future session, add an explicit end time so you know when normal idle behavior should return.