Written for Synergy 3 (v3.7.2) and Synergy 1 (v1.21.4), checked 3 October 2026.
Operating system: Windows
When trying to install Synergy 1 or Synergy 3 on Windows, you may see an error message saying "Service cannot start", or this one, which names the app's service (Synergy Core Daemon in Synergy 3, Synergy in Synergy 1):
"Service 'Synergy Core Daemon' (Synergy Core Daemon) failed to start. Verify that you have sufficient privileges to start system services."
Despite the wording, this is not about permissions. To fix this, install the latest Microsoft Visual C++ Redistributable, then run the installer again: Latest supported Visual C++ Redistributable downloads
The same fix applies if Synergy 1 or Synergy 3 shows a Dependency Error window saying the installed Microsoft Visual C++ Runtime is outdated.
This shouldn't happen, since the Microsoft Visual C++ Redistributable is actually packaged together with our Windows installer, but there are some situations that cause Windows to have problems with the packaged redistributable.
On Windows 7
With Synergy 1, install the Visual C++ Redistributable for Visual Studio 2019 instead, then run the installer again.
For 64-bit Windows 7 (most computers): Visual C++ Redistributable for Visual Studio 2019 (64-bit)
For 32-bit Windows 7: Visual C++ Redistributable for Visual Studio 2019 (32-bit)