: Users with a physical retail disc can use their product key to activate a digital copy on Steam. Go to Add a Game > Activate a Product on Steam and enter your CD key. This will automatically download the 1.6.6 version.
Run the installer. The client will automatically detect your Steam or GOG installation of Forged Alliance. If you have a disc version, point the client to the install folder (e.g., C:\Program Files (x86)\THQ\Gas Powered Games\Supreme Commander - Forged Alliance ). Supreme Commander Forged Alliance Patch 1.6.6 Download
Once the FAF Client launches and logs you in (create a free account if needed), it will automatically verify your game files. The client will then download the latest patch— currently Patch 1.6.6 —along with all supporting mods and map pools. This is a ~200MB download depending on your existing files. : Users with a physical retail disc can
Do not interrupt the process. The FAF Client backs up your original game files and overwrites them with the patched versions. It also installs the FAF launcher, which is your new gateway to the game. Run the installer