The app is not code-signed (we're an independent developer), so Windows shows a one-time warning on first launch.
- Run the downloaded synclingo-setup.exe.
- If “Windows protected your PC” (SmartScreen) appears, click More info → Run anyway.
- It installs per-user (no admin prompt) and the app starts.
This warning is normal for unsigned apps and does not affect how the app works. Updates install automatically the same way.