To ensure a secure installation, always use official Fortinet sources. Direct links often require a login to the Support Portal. Fortinet Product Downloads | Support
Go to > Firmware Download (or FortiCare Legacy > Downloads in some views). Select FortiClient from the product dropdown menu. Locate Version 6.0.10 :
Only use 6.0.10 in air-gapped networks or transient test environments. Never expose a PC running this client to the public internet.