When installing or launching a game, Steam presents the error "Game is not available on your current platform."
This error message means that the game is not supported on the operating system that you are currently using. You can check each game's system requirements and compatible operating systems on that game's Steam Store page.
Games that list SteamPlay on their Steam Store page can be played on any of the two or more operating systems that are listed next to the SteamPlay icon.
When checking system compatibility with a specific game, ensure that you check the game's hardware requirements in addtion to compatible operating systems.
Most Steam games can be played on a supported Windows operating system. Ensure that you check which versions of Windows are supported for any game that you are interested in purchasing. Most games that support Windows 7 will also work with Windows 8.
A list of featured Mac OSX games can be found here:
You can also perform a search within the Steam Store and then select "Mac" in the operating system dropdown box to filter to Mac OSX compatible results only.
Be sure to check the specific version of OSX that is required for any game that you are insterested in.
Steam and its games are currently only supported on Ubuntu with Unity, Gnome, or KDE desktops.
A list of featured Linux games can be found here:
You can also perform a search within the Steam Store and then select "Linux" in the operating system dropdown box to filter to Linux compatible results only.
Some users will deliberately purchase a game that is not available on their operating system with the aim of running the game with emulators or other utilities that simulate the game's system requirements. Be aware that purchases made with this goal in mind are not supported by Steam Support.