Windows VPN Client version 4.1.3 and higher installation fails on windows server 2012 R2 or on Windows 8.1.
The Cato InstallShield wizard is interrupted during the installation. The OS driver signature enforcement blocks the Cato VPN client drivers installation.
You have to disable driver signature enforcement in the windows advanced boot options as described in the following link:
https://docs.microsoft.com/en-us/archive/blogs/emberger/windows-server-2012-r2-install-unsigned-drivers and afterwards install the Cato VPN client.
Another workaround is to install Cato Client version 4.0.6 or earlier and then upgrade to version 4.1.x or later.
For more about Windows Client installation issues, see Troubleshooting Cato Windows VPN Client Installation Issues.