Running Safely with the Lid Closed

Keep Awake alone does not survive a closed lid

This is the single most common mix-up: turning on Keep Awake, closing the lid, and expecting the work to keep running. It won't — macOS puts the Mac to sleep the moment the lid shuts, regardless of what keep-awake mode is active. Keep Awake, Timer, Charging Only, and Auto Mode all hold off idle sleep, but none of them override the lid-close sleep on their own.

The reason is architectural, not a LidRun shortcoming: those modes hold an IOKit power assertion, and an assertion only blocks idle sleep — the sleep macOS triggers because nothing's been touched in a while. Closing the lid fires a separate, lower-level clamshell sleep that no assertion can stop. The only lever that prevents lid-close sleep on battery is a system-wide setting, pmset disablesleep, which needs administrator privileges to change. That's what Closed-Lid mode actually flips for you — and why macOS asks for a password the first time, before the Helper is enabled.

Closed-Lid mode is the one setting that actually changes this behavior. If you need work to keep running with the lid shut, that's the mode to turn on — not just Keep Awake.

One exception: if the Mac is on AC power with an external display and a keyboard or mouse attached, macOS already keeps it awake with the lid closed on its own — that's native Apple clamshell support, not something LidRun adds. Closed-Lid mode matters for the case that isn't covered: running on battery, or with no external display.

Turn on Closed-Lid mode correctly

Click the menu bar icon and select Closed-Lid Mode. You'll see two options: 'Sleep when done', marked Recommended, where the Mac sleeps automatically once the job actually finishes, and 'Stay awake until I turn it off', which stays awake indefinitely until you end it yourself.

'Sleep when done' watches for tracked AI or dev work and, once none has been active for a set idle window — 10 minutes by default, adjustable to 20 or 30 — asks the Mac to sleep. That's a shorter window than the general Auto Sleep default, on purpose: a closed lid runs warmer, so there's less reason to hold it open once the work is actually finished.

Pick one, confirm, and only then close the lid. Turning on Closed-Lid mode after the lid is already closed doesn't work — the sequence matters.

If you haven't enabled the LidRun Helper yet, macOS will ask for your administrator password each time this turns on — that's the same disablesleep permission prompt from above, not a LidRun nag. See Enable the LidRun Helper to skip that step going forward.

The safety habits that actually matter

Airflow is the one thing no app can fix for you. Keep the Mac on a hard, flat, ventilated surface — never inside a closed bag or backpack while a job is running. A closed-lid Mac generates real heat, and a sealed enclosure traps it. If you're planning to move around with it running — a backpack for the commute, say — 'Sleep when done' is the safer of the two modes: it ends the session as soon as the work does, instead of holding the Mac awake indefinitely inside a bag.

LidRun watches your battery level and thermal state throughout the session and can back off on its own. Settings → Safety has a graduated battery scale: a heads-up warning at 15% by default, a stronger warning at 5%, and a force-sleep floor at 4% that releases every keep-awake hold and asks the Mac to sleep outright, so it can't run itself down to a hard shutdown. That floor always runs, even with other warnings turned off, and can only be raised, never pushed below 4%. Separately, an auto-stop threshold — 20% by default, adjustable from 15% up to 50% — ends a keep-awake session before the battery gets anywhere near that low. On the thermal side, 'Drop Closed-Lid if the Mac gets too hot' (on by default in Settings → Safety) automatically ends Closed-Lid mode if the chip reaches macOS's 'critical' thermal level.

That safety net only works if you've actually left it configured — check it before a long overnight run, not after. And it only steps in when the Mac is genuinely idle or unsafe: a Mac that's actively in use is never forced to sleep.

Crashes are the other edge case worth knowing about. If LidRun quits or is force-quit while Closed-Lid mode is on, the disablesleep setting stays flipped on — the Mac won't fall back to sleeping on its own. LidRun checks for that leftover state the next time it launches and resets it automatically, but that recovery only fires on the next launch, not while the Mac is sitting there mid-session, and without the Helper enabled it asks for your admin password again, the same as turning the mode on does.

Be honest about what this is: LidRun helps reduce risk, it isn't a guarantee that nothing goes wrong. The same promise — agent running, stay awake; agent done or unsafe, release and sleep — applies with the lid closed as with it open. Placement and airflow are still your responsibility.