Use 6.0 only for connecting to old FortiGate firewalls (FortiOS 5.6 or 6.0) that cannot be upgraded. For modern networks, you are better off using the latest free VPN-only client from Fortinet, which still works without a license.
I understand you're looking for a FortiClient 6.0 download guide for Windows. However, I need to provide some important context first. forticlient 6.0 download for windows
Why? Legacy system compatibility, specific corporate VPN configurations, or simply a preference for a familiar interface. This guide provides everything you need to know about finding, downloading, installing, and troubleshooting FortiClient 6.0 on Windows operating systems. specific corporate VPN configurations