Written for Synergy 3 (v3.7.2), checked 3 October 2026.
Operating system: Windows, macOS, and Linux
What is the background service?
The background service is a special process (synergy-service) in Synergy 3 that runs the auto-discovery, config-sync, and many other functions. It communicates over your LAN (local area network) between all computers which Synergy 3 is installed on.
Send us a diagnostic report
If you see a background service error, please send us a diagnostic report from each computer. It tells us what went wrong so we can fix it. For the steps, see: How to get diagnostic info?
In the meantime, try the steps below.
Service version is out of date?
If Synergy 3 shows Service version is out of date., click Restart local background service in that message. If that doesn't help, restart the computer.
Complete reinstall
The most reliable way to fix most issues related to the background service in Synergy 3 is to completely uninstall Synergy 3 and then reinstall Synergy 3. For the steps, see: How to reinstall or uninstall Synergy 3
It is very important that you follow the instructions carefully; especially the uninstall instructions for deleting config files, and also the order in which you should uninstall, reboot, then install. Rebooting after uninstalling, as well as deleting the config files on disk seems to solve most problems.
If that doesn't solve the problem, please continue reading.
macOS security settings
If you're using a Mac, there could be a problem with the macOS permissions Synergy 3 needs. Sometimes this fails silently and provides no information about an error. For the steps to fix it, see: Troubleshooting macOS Device Control and Data Access (previously Security & Privacy in Accessibility)
Run the reinstall commands
The synergy-service process comes with a built-in way of reinstalling itself. This will potentially remove any invalid files, and recreate the required files that it needs to function properly.
Windows
Start the Command Prompt app (run as Administrator) and run the following, which starts the background service again:
"C:\Program Files\Synergy\synergy-service" -i
macOS
Start the Terminal app and run the following:
/Applications/Synergy.app/Contents/MacOS/synergy-service -u /Applications/Synergy.app/Contents/MacOS/synergy-service -i
Linux
Start the Terminal app and run the following. Both commands need sudo; you'll be asked for your password:
sudo /opt/Synergy/synergy-service -u sudo /opt/Synergy/synergy-service -i