Waking a sleeping Mac

Swipe left on it in your paired list and choose "Wake" (Wake-on-LAN), then connect. Prerequisite: "Wake for network access" is enabled in the Mac's System Settings → Battery/Energy; it's most reliable when plugged in or on wired Ethernet.

• The Mac has to stay powered on with TouchNow Host running — a quit app accepts no connections.
• Don’t close the lid on a MacBook; closing it sleeps the machine immediately.
• Leave it plugged in when you go out. On battery, macOS also shuts the Wi-Fi down, and nothing remote can wake it.
• In System Settings, turn on “Prevent automatic sleeping when the display is off”. It is under Battery → Options on a MacBook, and under Energy Saver on a desktop Mac. The screen still goes dark; the machine just doesn’t sleep hard.

When Wake-on-LAN wakes your Mac, it enters DarkWake: the machine is running, the network is up, and Host accepts your connection — but the display has no power yet. No display means no framebuffer, so the screen-capture API starts successfully and then delivers zero frames. What you see is "connected, but stuck on receiving".

This is not a slow network and not a missing permission. macOS’s "prevent idle system sleep" does not help here, because what follows DarkWake is Maintenance Sleep, not idle sleep.

TouchNow Host handles it by declaring user activity (IOPMAssertionDeclareUserActivity) when it detects the display is still asleep. Measured on our machines, that promotes DarkWake to a full wake and lights the screen within 38 milliseconds. Capture is held back until the display is actually awake (up to 6 seconds) so it never spins with nothing to record.

To check it yourself, run pmset -g log on the Mac and look for the DarkWake lines. A successful wake is logged as HID Activity.

A Wake-on-LAN packet only travels within one local network, so in theory you cannot wake your Mac from the road. In practice (measured on macOS 26, Apple Silicon) a sleeping Mac still wakes, through a different path.

While macOS sleeps, the network card keeps already-established TCP connections alive — you can see TCPKeepAlive=active in pmset -g log. Host’s signaling connection stays in the room through sleep, so when your iPhone joins, the notification the server pushes is enough to trigger a DarkWake (logged as a wifibt wake). This works across networks and needs no router setup.

But it does expire. The log shows powerd request=TCPKATurnOff wakeAt= followed by a time about four days out — sleep longer than that and the mechanism is quietly switched off, which is why it can feel like "sometimes it wakes, sometimes it does not". If you will be away for a long time, keeping the Mac awake, or turning on "Prevent automatic sleeping when the display is off", is more reliable.

One thing that often gets conflated: a MacBook sleeping on battery turns Wi-Fi off entirely, so Wake-on-LAN cannot work — that is an Apple limitation. The TCP-keepalive path above still worked at 2% battery in our tests. They are not the same mechanism.