Software
Main articles: Mac OS, Mac OS history, and Mac OS X
The original Macintosh was the first successful computer to use a graphical user interface devoid of a command line. It used a desktop metaphor, depicting real-world objects like documents and a trashcan as icons onscreen. The System software introduced in 1984 with the first Macintosh and renamed Mac OS in 1997, continued to evolve until version 9.2.2. In 2001, Apple introduced Mac OS X, based on Darwin and NEXTSTEP; its new features included the Dock and the Aqua user interface. The most recent version is Mac OS X v10.5 "Leopard". In addition to Leopard, all new Macs are bundled with assorted Apple-produced applications, including iLife, the Safari web browser and the iTunes media player.

Mac OS X enjoys a near-absence of the types of malware and spyware that affect Microsoft Windows users.[53][54][55] Worms as well as potential vulnerabilities were noted in February 2006, which led some industry analysts and anti-virus companies to issue warnings that Apple's Mac OS X is not immune to viruses, as is commonly misconceived.[56][57][58] However, there has not been an outbreak of Mac malware, and Apple routinely issues security updates for its software.

Following the release of the Intel-based Mac, third-party virtualization software such as Parallels Desktop, VMware Fusion, and Crossover Mac began to emerge, allowing users to run Microsoft Windows or previously Windows-only software, on Macs at near native speed. A BIOS compatibility module for Intel-based Macs allows users to run Windows natively. Apple also released Boot Camp, which helps users to install Windows XP or Vista, along with Mac-specific Windows drivers, and dual boot between Mac OS X and Windows, on these Macs. Because Mac OS X is less common than Microsoft Windows, less third-party software is available,[59] although popular applications such as Microsoft Office, are usually cross-platform and Mac versions run without Windows emulation.