If you have recently upgraded you mac to the latest macOS Catalina 10.15 version you will receive the following error when trying to run Synergy:
The development team is working on an update to resolve this. In the meantime, please use the following workaround:
- Open the Applications folder in Finder.
- Right-click on Synergy and click "Run".
- A new OS warning dialog will show up, but it will let Synergy run.
- After doing this one time, the next time you open Synergy it will run as normal.