Mac OS X Snow Leopard (version 10.6) is the seventh major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers.Snow Leopard was publicly unveiled on June 8, 2009 at the Apple Worldwide Developers Conference. On August 28, 2009, it was released worldwide, and was made available for purchase from Apple's website and its retail stores at the price of US$29 for a single-user license.