Mac OS X Snow Leopard

Mac OS X Snow Leopard, or Mac OS X 10.6, is the seventh major release of Mac OS X that was released on 28 August 2009. It was announced on 9 June 2008 at WWDC. Snow Leopard is one of Apple's longest lasting Mac OS X operating systems with five years of support and launched with largely positive reviews. It is a minor update over Mac OS X Leopard, focusing primarily on performance improvements.

This is the last version of Mac OS X to be distributed on optical discs as subsequent releases starting with Mac OS X Lion would only be distributed exclusively through the Mac App Store.

This is the last version of Mac OS X to include Rosetta, and thus the last version to support PowerPC-only applications.

Differences from Leopard

 * Removed support for the PowerPC architecture due to Apple's intent to support Intel processors.
 * Finder has been rewritten in Cocoa to take the advantages of Mac OS X. Before that, Finder was based on the Carbon API.
 * On 64-bit systems, the kernel now also runs in 64-bit.
 * Most built-in applications now support 64-bit.
 * Version 10.6.6 introduced the Mac App Store, an ESD marketplace for free and paid programs for macOS.