Automatically sets your Mac's display to maximum resolution with Dynamic Resolution enabled whenever an incoming Screen Sharing session is detected, then restores the original settings when the session ends.

Every time I connect to my Mac remotely via Screen Sharing, the same annoying ritual plays out: the display is stuck at a low resolution, text is blurry, and I have to dig into System Settings → Displays, manually pick a higher resolution, and toggle "Dynamic resolution" on — before I can actually get any work done. Then when I disconnect it's still changed.

This tool eliminates that entirely. It watches for incoming connections and handles everything automatically, so Screen Sharing just works at full resolution the moment you connect.

• Detects an incoming Screen Sharing / VNC connection on port 5900
• Waits a few seconds for the display to settle, then switches to the highest available resolution with Dynamic Resolution enabled
• Intelligently handles locked screens — automatically retries if the machine is at the login window, waiting for you to unlock before applying the resolution change
• Restores your original display settings when the session ends
• Runs silently in the background as a LaunchAgent, starting automatically at login

1. Polls for active connections on port 5900 (macOS Screen Sharing / VNC).
2. On connection: waits a few seconds for the display to settle, then:
   • Uses displayplacer to switch the host display to the highest available resolution.
   • Calls SLSDisplaySetDynamicGeometryEnabled via the SkyLight private framework — the same API that System Settings > Displays uses for the "Dynamic resolution" toggle.
   • If the machine is locked: detects the lock state and automatically retries, re-querying the display configuration after each unlock attempt (display IDs can change after login).
3. On disconnect: restores the original resolution and dynamic resolution state.
4. A LaunchAgent keeps it running in the background, restarting automatically at login.

• macOS 13 Ventura or later (tested on Ventura, Sonoma, and Sequoia — Apple Silicon and Intel)
• Xcode Command Line Tools: xcode-select --install
• Homebrew (used to install displayplacer)
• Screen Sharing enabled on the host: System Settings → General → Sharing → Screen Sharing

Note: Dynamic Resolution relies on a private SkyLight framework API — the same one System Settings uses internally. It works on all currently supported macOS versions but could theoretically break on a future release.

Clone to the host Mac and run:

bash install.sh

The installer will:

• Install displayplacer via Homebrew if needed
• Compile the set-dynamic-resolution helper binary
• Register and start a LaunchAgent that persists across reboots

bash uninstall.sh

Edit the variables near the top of resolution-fixer.sh:

After changing configuration, reload the service:

launchctl unload ~/Library/LaunchAgents/com.resolution-fixer.plist
launchctl load ~/Library/LaunchAgents/com.resolution-fixer.plist

Or simply re-run bash install.sh to update and reload.

tail -f ~/Library/Logs/resolution-fixer.log

• Confirm Screen Sharing is enabled and a client can connect.
• Check that displayplacer works: displayplacer list
• Check logs: tail -f ~/Library/Logs/resolution-fixer.log

When connecting to a locked Mac, the tool will:

1. Detect the lock state (login window or screensaver)
2. Retry automatically every 3 seconds (configurable via RETRY_DELAY)
3. Re-query the display configuration on each attempt (display IDs can change after unlock)
4. Apply the resolution change as soon as you unlock the machine

Check the logs to see retry attempts:

tail -f ~/Library/Logs/resolution-fixer.log

launchctl list | grep resolution-fixer

A 0 in the first column means it is running. A non-zero number is the last exit code.

./set-dynamic-resolution --query   # show current state
./set-dynamic-resolution           # enable
./set-dynamic-resolution --off     # disable