MacOS

• 1. Introduction

  ›

  macOS is the operating system that has run Apple's Mac computers since 2001, and its roots stretch back to a company that Steve Jobs built after being pushed out of Apple. Today it holds the position of the second most widely used desktop operating system in the world, behind only Microsoft Windows. How did a piece of software born from a failed rival company become the backbone of one of the most recognized technology brands on earth? And why did it take nearly two decades before its version number ever climbed above ten? Those are the questions this documentary sets out to answer.

• 2. From NeXT to Apple

  ›

  Steve Jobs founded NeXT in 1985 after departing Apple, and the Unix-like operating system his team built there, called NeXTSTEP, launched in 1989. Its kernel drew from the Mach kernel originally developed at Carnegie Mellon University, layered with code from FreeBSD and other BSD operating systems. The graphical interface was built around an object-oriented toolkit using the Objective-C programming language.

  Throughout the 1990s, Apple had tried and failed to build a next-generation operating system through projects named Taligent, Copland, and Gershwin. All were eventually abandoned. The failures left Apple with no clear path forward, and in 1997 the company acquired NeXT, bringing NeXTSTEP along as the foundation for what would become macOS.

  The acquisition brought back Jobs himself, first as interim and then as permanent CEO. His task was to take the programmer-oriented OPENSTEP and reshape it into a system that everyday home users and creative professionals would actually want to use. That project carried the codename "Rhapsody" before it was officially named Mac OS X.

• 3. A Rocky Launch

  ›

  On the 24th of March 2001, Apple released Mac OS X 10.0, internally codenamed Cheetah. Critics who reviewed it found a striking tension: the new Aqua interface, with its translucent colors, pinstripes, and drop shadows, was visually arresting, but the system underneath was painfully slow. Ars Technica columnist John Siracusa, who reviewed every major release through version 10.10, later described those early releases as "dog-slow, feature poor" and called Aqua "unbearably slow and a huge resource hog."

  Adobe Inc., the developer of FrameMaker, declined to build a new version of that application for Mac OS X, a decision that reflected how uncertain the platform's future looked. The Aqua interface had been explicitly designed to appear "lickable," but even Bruce Tognazzini, who had founded Apple's original Human Interface Group, argued it represented a step backwards in usability compared with the classic Mac OS.

  Apple released version 10.1 just six months later, in October 2001, adding DVD playback and performance improvements. That same version was handed out as a free upgrade CD to users already on 10.0. Beginning in January 2002, Apple made Mac OS X the default operating system preinstalled on all new Macs.

• 4. Building Momentum

  ›

  Mac OS X 10.2 Jaguar, released on the 23rd of August 2002, was the first version Apple publicly promoted by its codename. It included over 150 new user-facing features, among them Quartz Extreme for hardware-accelerated graphics compositing and the iChat instant messaging client. That same release replaced the classic Happy Mac startup icon with a grey Apple logo, a signal that the old era had formally ended.

  When Mac OS X Tiger arrived in April 2005, it reportedly shocked executives at Microsoft. Tiger introduced fast file searching through Spotlight and improved graphics processing, capabilities Microsoft had spent years struggling to add to Windows Vista. On the 10th of January 2006, Apple shipped the first Intel-based Macs alongside the 10.4.4 update to Tiger, marking the beginning of a processor transition that had been quietly maintained as a contingency plan for years.

  The release of Mac OS X Leopard on the 26th of October 2007 brought Apple's claim of more than 300 new features, including Time Machine for automatic backups and Boot Camp preinstalled. Leopard was also the first BSD-based operating system to receive UNIX 03 certification on the Intel platform. That version quietly carried another distinction: it was the last release to support Macs built around PowerPC processors.

• 5. The Processor Transitions

  ›

  Apple's move from PowerPC to Intel was not made on a whim. As far back as April 2002, a report described a secret project codenamed Marklar: a version of Mac OS X kept running on Intel x86 processors, maintained as a hedge in case Apple grew dissatisfied with PowerPC's progress. On the 6th of June 2005, Steve Jobs confirmed at his WWDC keynote that Apple had indeed been running Mac OS X on Intel processors for most of its developmental life.

  The bridge technology that made the transition workable was Rosetta, a binary translation layer that let software compiled for PowerPC run on the new Intel machines. Rosetta shipped with OS X through version 10.6.8 before being discontinued with Lion in 2011. Mac OS X 10.6 Snow Leopard, released on the 28th of August 2009, was the first version built exclusively for Intel hardware, and it was explicitly branded to developers as a "no new features" release focused entirely on performance and stability.

  A second transition began at WWDC 2020, when Apple announced on the 22nd of June that it was shifting Mac hardware to its own ARM-based processors. The company estimated the move would take about two years; it actually took three, completing at WWDC 2023 with the announcement of the Apple silicon Mac Pro. A new version of Rosetta, called Rosetta 2, handled Intel software on the new machines. The shift also enabled Macs with ARM processors to run iOS and iPadOS apps natively.

• 6. Design in Constant Motion

  ›

  Few operating systems have changed their visual language as often as macOS. Aqua arrived in 2001 with water-like elements: soft edges, translucent colors, and spatial anti-aliasing on every element. Third-party developers immediately began producing skins for other operating systems that mimicked its look, prompting Apple to threaten legal action against those it believed had crossed into copyright infringement.

  In 2011, with Lion and Mountain Lion, Apple pushed a heavily skeuomorphic direction borrowed from iOS at the time, including a file-system browser that resembled physical leather and a backup utility that showed past file versions against a swirling nebula. That direction proved divisive. In 2012, Apple removed Scott Forstall, the head of OS X development, and the design language shifted course.

  OS X Yosemite in 2014 adopted the flat, deeply color-saturated aesthetic that iOS 7 had introduced the year before. In 2025, macOS Tahoe introduced Liquid Glass, a new design language described as partly inspired by the original Aqua. Tahoe also unified Apple's version numbering: rather than continuing the sequential count from Big Sur onward, all of Apple's operating systems now use the number of the year following their release, so macOS Tahoe, released in September 2025, carries version number 26.

• 7. Security and the Wider Ecosystem

  ›

  In its earlier years, Mac OS X had a near-absence of the malware and spyware that troubled Windows users. That quiet period ended around 2006, when analysts began noting that the platform was not immune. By early 2011, a wave of malware including Mac Defender, MacProtector, and MacGuard was spreading, with later versions installing without requiring the user's administrative password. An estimated 100,000 users were affected before Apple issued a fix. Apple had initially instructed support staff not to acknowledge the issue.

  Apple later built Xprotect, an anti-malware feature, into the system beginning with Snow Leopard. Security updates are now released regularly, though only the most recent major release receives patches for all known vulnerabilities. In 2021, a critical privilege escalation flaw was fixed in Big Sur while the previous release, Catalina, went without a patch for 234 days, until Apple was informed the vulnerability was actively being used to infect machines belonging to people visiting Hong Kong pro-democracy websites.

  macOS Ventura added Rapid Security Response updates, which can install in under a minute and require only a brief reboot. Ventura also introduced Lockdown Mode, an optional setting designed for journalists, activists, and public figures at risk of targeted cyberattacks. Among its restrictions: disabling just-in-time compilation for Safari's JavaScript engine, blocking FaceTime calls from unknown contacts, and requiring approval before any new accessories connect. The 2025 WWDC announcement that macOS Tahoe will be the last version to support Intel-based Macs sets the stage for whatever comes next in that security landscape.