Overview
When a Luna Display session is active, Luna Secondary holds background processes that prevent your secondary Mac from sleeping automatically. This means that when your host Mac's display turns off or sleeps, the secondary Mac stays awake and sits on a frozen last frame.
This article walks through a workaround that detects when your host Mac's display sleeps and immediately tells the secondary Mac to sleep as well, which clears the session properly.
NOTE:
This workaround is intended for users comfortable with Terminal and basic Mac configuration.
What you'll need
Both Macs on the same local network
Terminal access on both Macs
Homebrew installed on your host Mac
Hammerspoon (free, installed via Homebrew in Step 3)
Setup
Step 1: Enable Remote Login on the secondary Mac
On your secondary Mac, go to System Settings > General > Sharing and turn on Remote Login.
Then, on your host Mac, open Terminal and run the following to copy your SSH key over so the connection is passwordless.
Replace
<user>with the username on your secondary Mac and<receiver-mac>with its hostname or local IP:
ssh-copy-id <user>@<receiver-mac>.local
To verify it worked, run:
ssh <user>@<receiver-mac>.local 'echo connected'
You should see
connectedprinted back without being prompted for a password.
Step 2: Create a sleep script on the host Mac
On your host Mac, open Terminal and create the following file:
nano ~/.displaysleep
Paste this in, replacing
<user>and<receiver-mac>with the same values as above:
#!/bin/bash ssh -o ConnectTimeout=5 <user>@<receiver-mac>.local 'pmset sleepnow' 2>/dev/null
Save and close the file (in nano: Control+O, then Control+X), then make it executable:
chmod +x ~/.displaysleep
Step 3: Install Hammerspoon and set up the sleep trigger
Install Hammerspoon via Homebrew:
brew install --cask hammerspoon
Open Hammerspoon, grant it Accessibility permission when prompted, and set it to Launch at Login in its menu bar icon.
Then open or create the Hammerspoon config file:
nano ~/.hammerspoon/init.lua
Paste in the following:
sleepWatcher = hs.caffeinate.watcher.new(function(event) if event == hs.caffeinate.watcher.screensDidSleep then hs.execute("/Users/<user>/.displaysleep") end end) sleepWatcher:start()Replace
<user>with your host Mac's username. Save and close the file.Back in Hammerspoon, click Reload Config from the menu bar icon.
Test it
In Terminal on your host Mac, run:
pmset displaysleepnow
Your secondary Mac should sleep within about a second. When your host Mac wakes up, Luna Secondary will reconnect automatically.
Why Hammerspoon instead of sleepwatcher?
Sleepwatcher is a common tool for this kind of task, but its display-sleep callback does not fire reliably on recent versions of macOS. Hammerspoon catches the display-sleep event consistently.
Notes
This workaround triggers on display sleep, not full system sleep. These are separate events on macOS, and display sleep is the one that matters for most setups.
If your host Mac is set to stay awake while plugged in but let the display turn off, this workaround should still catch that correctly.