This update is recommended for all versions of Mac OS X v10.6 through 10.6.6 Snow Leopard, and includes general operating system fixes that enhance the stability, compatibility, and security of your Mac; including fixes that: Improve the reliability of Back to My Mac. Resolve an issue when transferring files to certain SMB servers. Download Mac OS X Snow Leopard. Apple unveiled Mac OS X Snow Leopard at SAN FRANCISCO on June 8, 2009, Snow Leopard is an even more powerful and refined version of the world’s most advanced operating system and the foundation for future Mac innovation.