Help · Mac
Keeping the Mac awake
The switch
The hero switch — in the main window, in the menu bar popover, or the Block Screensaver button on your phone — is the master switch. On, the Mac neither starts the screensaver nor goes to sleep on its own. Off, macOS is back in charge.
The switch reflects any reason the Mac is being kept awake: manual, a running timer, or an
agent session. Turning it off from the window or the menu bar ends all of them, agent
sessions included — that is why it is the master switch. Turning blocking off from the
phone (or through the unblock-screensaver URL) is gentler: it cancels a running timer
but deliberately leaves agent sessions running, because nothing off the machine may abort an
agent’s work.
The three reasons can overlap. A timer started while you were already blocking manually adds the timer reason; when the timer ends, the Mac sleeps regardless. The status shown — Idle, Keeping awake (“Screensaver blocked”), Timer running, Agent session — is one of four, resolved in that order of precedence: an agent session shows as agent, else a running timer as timer, else manual blocking as blocked.
The rules that stop blocking on their own
Settings ▸ Keep Awake — one card, Stop keeping the Mac awake when…. Each is a switch; the journal records which one fired (“Blocking released — …”).
| Rule | Default | What it does |
|---|---|---|
| Lid closed / system sleep | On | Stop blocking when the Mac goes to sleep. |
| Screen lock | On | Stop blocking when you press the power button or lock the screen (⌃⌘Q), so the Mac can fall asleep on its own. |
| Display sleep | On | Stop blocking when the displays are put to sleep manually (⌃⇧⏏ or a hot corner). |
| Screensaver started anyway | Off | Stop blocking if the screensaver starts anyway, e.g. via a hot corner. |
| Low battery | On | Stop blocking — including agent sessions — when the battery drops below the threshold (10 % by default; the picker beside the switch). |
Two more releases happen without a switch: when your macOS user session is switched away (“Blocking released — user switched”), and when blocking ended for a reason the app could not name (“Blocking ended unexpectedly”).
At launch
Settings ▸ General ▸ When AtControl starts: Keep the Mac awake, Leave it off, or Restore the last state. With Restore the last state, a Mac that was power-cut while blocking comes back blocking, and the journal closes the interrupted session at the moment the app was last known alive — not at the relaunch, which would credit it with every hour the Mac was off.
Surviving a crash
Blocking is two journal events, an “on” and an “off”. If the app is killed it writes only the first. AtControl stamps a heartbeat every 30 seconds while anything is held awake, and on the next launch closes the orphaned session at that stamp. Statistics stay honest.
Where it shows
- The hero card in the window: status, a coloured band with “Awake since 14:03 · for 24 min”, and the switch.
- The menu bar icon changes with the status: idle, blocked (green), timer (amber, with the countdown), agent (purple).
- The phone, after pairing: presence (Online / Recently seen / Sleeping / Offline) and mode, separately.