MacOS

macOS is a special computer system made by Apple for its Mac computers. It began in 2001 and has been updated many times.

The first version, called Mac OS X 10.0, came out on March 24, 2001. Over the years, macOS has changed a lot. It now works with different types of computer chips, including Apple's own ARM-based chips. Each version has a special name, often after places in California.

Today, macOS is very popular for desktop and laptop computers. It is used after Microsoft Windows but before Linux and other systems. As of 2026, the latest version is macOS 26 Tahoe. macOS is also the base for many other Apple systems, like those used on iPhones, iPads, and Apple Watches.

History

Development

The story of macOS began at NeXT, a company started by Steve Jobs after he left Apple in 1985. There, they created the Unix-like NeXTSTEP operating system in 1989. NeXTSTEP used the Mach kernel from Carnegie Mellon University, with parts from FreeBSD and other BSD systems. Its graphical user interface was built using the Objective-C programming language.

In the 1990s, Apple tried to make a new operating system through projects like Taligent, Copland, and Gershwin, but they stopped. In 1997, Apple bought NeXT, and NeXTSTEP, later called OPENSTEP, became the base for Apple’s new operating system. This brought Steve Jobs back to Apple, who helped turn OPENSTEP into a system for everyday users and creative people. The project was called “Rhapsody” before it was named Mac OS X.

Mac OS X

The “X” in Mac OS X means the number ten. The first version, Mac OS X Server 1.0, looked like the older classic Mac OS but didn’t work with older Mac software. The version for everyday users, Mac OS X 10.0, came out in March 2001. It had a beautiful Aqua interface, but some thought it was slow. Apple quickly made new versions. By 2002, Mac OS X was on all new Macs. Later versions like Mac OS X Jaguar, Mac OS X Panther, and Mac OS X Tiger added many new features.

Apple also made popular products like the iPod, iTunes, and GarageBand. They created the iLife suite and the Safari web browser. With the internet growing, Apple offered online services like .Mac, MobileMe, and later iCloud. They also started the Mac App Store for software.

Newer versions of Mac OS X changed the look, moving away from the shiny styles of the early versions. Some apps got a brushed metal look. In Mac OS X Leopard (10.5), Apple made the interface more uniform. In 2006, the first Intel Macs came with a special version of Mac OS X Tiger.

A big change came with the iPhone in 2007. The iPhone used a version of Mac OS X, later called iPhone OS and then iOS. This made Apple focus more on Mac OS X because many iPhone developers wanted to make Mac software.

In 2007, Mac OS X Leopard came out for both Intel and older PowerPC Macs, but it was the last version for PowerPC Macs. In 2009, Mac OS X Snow Leopard (10.6) was only for Intel Macs and focused on improving speed instead of adding new features.

OS X

In 2012, the system was called OS X instead of Mac OS X. That year, Apple changed the design to be simpler. In 2013, OS X Mavericks (10.9) was a mix of old and new designs. The next version, OS X Yosemite (10.10), looked more like iOS 7 but worked better with a mouse.

macOS

In 2016, the system was renamed macOS to match Apple’s other operating systems like iOS, watchOS, and tvOS. macOS Sierra (10.12) added features like Siri, iCloud Drive, and a Night Shift mode for the screen. It also introduced a new file system called APFS. macOS High Sierra (10.13) in 2017 improved speed and added new technologies.

macOS Mojave (10.14) in 2018 added a dark mode and new wallpaper. macOS Catalina (10.15) in 2019 replaced iTunes with separate apps for music, TV, and podcasts.

In 2020, macOS Big Sur (version 11) was the first big change in the version number since 2000. It brought a new look and was the first macOS to run on Apple Silicon computers. Later versions like macOS Monterey (12), macOS Ventura (13), macOS Sonoma (14), and macOS Sequoia (15) continued this numbering.

In 2025, macOS Tahoe (version 26) will use the year number for its version, like Apple’s other systems. Tahoe also brought a new Liquid Glass design for all Apple products. In 2025, Apple said Tahoe would be the last version for Intel-based Macs.

Timeline of releases

Architecture

Main article: Architecture of macOS

macOS is built on the XNU kernel, which includes parts of the FreeBSD kernel. Apple releases this core as Darwin. On top of Darwin, Apple adds layers like the Aqua interface and the Finder to create macOS.

When macOS was first introduced as Mac OS X, it brought new features that made the system more stable and reliable than its predecessor, the classic Mac OS. Many parts of macOS's design come from OPENSTEP.

Software compatibility

See also: List of Mac software

Apple offers two main ways for developers to create software for macOS: Cocoa and Carbon. Cocoa works well with Apple’s newer systems, while Carbon helps older Mac programs run on macOS.

Cocoa was developed through a partnership between NeXT Computer and Sun Microsystems. Programmers often use the Objective-C language with Cocoa, though Apple now encourages using Swift. macOS can also run programs made for other Unix-like systems, such as Linux, using tools like Homebrew or MacPorts. Users can install applications from any source or through the Mac App Store, which checks that apps are safe.

Apple creates its own applications, such as iWork, Final Cut Pro, Logic Pro, iLife, and FileMaker. Many other companies also make software for macOS.

Hardware compatibility

Some people have made it possible to install newer macOS versions on computers Apple doesn’t officially support. This includes older Power Macintosh models and certain G3 and G4 Macs. While this works, it can be risky and isn’t supported by Apple.

PowerPC–Intel transition

Main article: Mac transition to Intel processors

In 2005, Apple announced it would switch from PowerPC to Intel processors over two years. Mac OS X was updated to run on both types of processors, using a tool called Rosetta to let older PowerPC programs run on Intel Macs. Support for PowerPC was later dropped, and new versions of macOS required Intel processors.

Intel–Apple silicon transition

Main article: Mac transition to Apple silicon

Rumors about Apple moving away from Intel processors began in 2011 and grew stronger in 2020 when Apple announced its shift to its own ARM-based processors. The first macOS version to support these new processors was macOS Big Sur. Later versions can run programs built for both Intel and Apple silicon. The transition finished in 2023 with the new Mac Pro, allowing Macs with ARM processors to run iOS and iPadOS apps directly.

Features

User interface

The macOS user interface has a menu bar at the top of the screen. It holds the Apple menu, application menus, and status menus. The Dock is at the bottom of the screen by default. It shows icons for open applications, file shortcuts, and the Trash.

Apple has changed the look of macOS over time. Since 2012, most Mac models have had high-resolution Retina displays, and macOS supports these displays well. Many applications follow Apple’s design rules, giving them a consistent look and keyboard shortcuts. Built-in features include spelling and grammar checks, a color picker, and a dictionary. macOS also makes it easy to view and create PDF documents.

Aqua

A big change from the old Mac OS to Mac OS X was Aqua. Aqua has a design with water-like looks. Every part of a window, including text and graphics, uses special technology to look smooth. Improvements to color matching help with printing and multimedia. New design parts like drop shadows and special boxes called sheets make the interface feel deeper and more three-dimensional.

The soft edges, see-through colors, and decorative lines made the interface feel more lively. After a design shift in iOS 7, OS X Yosemite moved to a simpler style. In 2025, macOS Tahoe used a new design called Liquid Glass, inspired by Aqua.

Built-in components

The Finder is a file browser that helps you find anything on your computer. Quick Look lets you preview files like videos and documents without opening other apps. Spotlight helps you search for files, photos, and more quickly.

Apple added Exposé, called Mission Control since version 10.7, which helps you switch between open windows and see your desktop. FileVault offers optional encryption to keep your files safe. Version 10.4 brought Automator for creating automatic tasks, Dashboard for small on-screen tools, and Front Row for watching media with a remote control. Sync Services keeps your calendar and contact information up to date across apps.

Since version 10.5, system icons can grow up to 512×512 pixels for better viewing in places like Cover Flow, a 3D way to browse files and media. That version also added Spaces for having multiple desktops, Time Machine for backing up files, and built-in Screen Sharing. macOS supports emoji characters and connects with social networks like Twitter and Facebook. Features from iOS, like the personal assistant Siri, have also come to macOS.

Multilingual support

macOS offers 47 system languages to choose from when you first set it up, and you can type in many different scripts. Updates have added better support for Chinese characters and connections with popular social networks in China.

Updating methods

You can update macOS using the Software Update settings in System Settings or a special command for advanced users. Until OS X 10.8 Mountain Lion, a separate Software Update app handled updates. In Mountain Lion and later, updates moved to the Mac App Store, though the way they update stays the same. Starting with macOS 10.14 Mojave, the update function returned to the Software Update settings pane.

Most Macs get six or seven years of updates. After a new version of macOS comes out, the two older versions still get some updates, but many security fixes only come to the latest version.

Release history

Timeline of versions

Mac OS X versions were named after big cats, except for Mac OS X Server 1.0 and the original public beta, from Mac OS X 10.0 until OS X 10.9 Mavericks. After that, Apple began using locations in California for the names. Before its release, version 10.0 was called "Cheetah" inside Apple, and Mac OS X 10.1 was called "Puma". After the excitement around Mac OS X 10.2, called "Jaguar", Apple started using these code names in marketing. Mac OS X 10.3 was called "Panther", Mac OS X 10.4 "Tiger", Mac OS X 10.5 "Leopard", Mac OS X 10.6 "Snow Leopard", Mac OS X 10.7 "Lion", OS X 10.8 "Mountain Lion", and OS X 10.9 "Mavericks".

"Panther", "Tiger" and "Leopard" are trademarks of Apple, but "Cheetah", "Puma" and "Jaguar" were not. Apple also registered "Lynx" and "Cougar" as trademarks, but let them expire. A store called Tiger Direct sued Apple for using the name "Tiger". On May 16, 2005, a US court decided that Apple did not break Tiger Direct's trademark.

Mac OS X Public Beta

Main article: Mac OS X Public Beta

On September 13, 2000, Apple released a US$29.95 "preview" version of Mac OS X, called Kodiak, to get feedback from users.

This version let people try the Aqua interface for the first time, and Apple made many changes based on what users said. Mac OS X Public Beta stopped working in Spring 2001.

Mac OS X 10.0

Main article: Mac OS X 10.0

On March 24, 2001, Apple released Mac OS X 10.0, called Cheetah inside Apple. The first version worked slowly, was not complete, and had very few programs available. Many critics thought it was not ready for everyday use, but they saw it as a starting point for future improvements. Releasing Mac OS X was a big achievement for the Macintosh community, as work on updating the Mac OS had been going on since 1996 with many delays.

Mac OS X 10.1

Main article: Mac OS X 10.1

Later that year, on September 25, 2001, Mac OS X 10.1, called Puma inside Apple, was released. It worked faster and added features like playing DVDs. Apple offered 10.1 as a free upgrade CD for 10.0 users, or for $129 for people using Mac OS 9. On January 7, 2002, Apple said Mac OS X would become the default operating system for all Macintosh products by the end of that month.

Mac OS X 10.2 Jaguar

Main article: Mac OS X Jaguar

On August 23, 2002, Apple released Mac OS X 10.2 Jaguar, the first version to use its code name in marketing. It made the system faster and updated the look of Aqua. Jaguar also added over 150 new features for users, including Quartz Extreme for graphics, a place to store contacts in the new Address Book, and the iChat messaging program. The Happy Mac icon — seen when the Mac starts up — was replaced with a grey Apple logo.

Mac OS X 10.3 Panther

Main article: Mac OS X Panther

Mac OS X v10.3 Panther came out on October 24, 2003. It made the system faster and updated the user interface a lot. Panther added many new features like an updated Finder, Fast user switching, Exposé for managing windows, FileVault for security, Safari for web browsing, iChat AV for video conferencing, better Portable Document Format support, and better compatibility with Microsoft Windows. It stopped supporting some older G3 computers like "beige" Power Macs and "WallStreet" PowerBooks.

Mac OS X 10.4 Tiger

Main article: Mac OS X Tiger

Mac OS X 10.4 Tiger was released on April 29, 2005. Apple said Tiger had more than 200 new features. Like Panther, it did not work on some older machines; Tiger needed a Mac with 256 MB of memory and a built-in FireWire port. New features in Tiger included Spotlight for searching, Dashboard for small programs, Smart Folders, an updated Mail program, QuickTime 7, Safari 2, Automator for automation, VoiceOver for helping people who can't see well, Core Image and Core Video. The first Apple TV used a changed version of Tiger. On January 10, 2006, Apple released the first Intel-based Macs with the 10.4.4 update to Tiger. This version worked the same on PowerPC and Intel Macs, except the Intel version did not support the Classic environment.

Mac OS X 10.5 Leopard

Main article: Mac OS X Leopard

Mac OS X 10.5 Leopard came out on October 26, 2007. Apple called it "the largest update of Mac OS X". It added more than 300 new features. Leopard worked on both PowerPC- and Intel x86-based Macintosh computers; it needed at least 867 MHz for G4 processors and 512 MB of RAM. The DVD worked for all supported Macs, including 64-bit machines. New features included a new look, an updated Finder, Time Machine for backups, Spaces for organizing windows, Boot Camp for running Windows, support for 64-bit applications, new features in Mail and iChat, and new security features. Leopard was an Open Brand UNIX 03 registered product on Intel computers. It was also the first BSD-based OS to get UNIX 03 certification. Leopard stopped supporting the Classic Environment and all Classic programs. It was the last version of Mac OS X to work on PowerPC computers.

Mac OS X 10.6 Snow Leopard

Main article: Mac OS X Snow Leopard

Mac OS X 10.6 Snow Leopard was released on August 28, 2009. Instead of big changes to the look and user features, Snow Leopard focused on improving speed, efficiency, and stability. For most users, the biggest changes were: more space freed after installing, a faster Finder rewritten in Cocoa, faster Time Machine backups, easier disk ejecting, a better Preview program, and a faster Safari web browser. Snow Leopard only worked on machines with Intel processors, needed at least 1 GB of RAM, and stopped default support for PowerPC programs (Rosetta could be added to keep support for PowerPC-only programs).

Snow Leopard also had new 64-bit technology for more RAM, better support for multi-core processors with Grand Central Dispatch, and better graphics performance with OpenCL.

The 10.6.6 update added support for the Mac App Store, Apple's place to buy macOS applications.

OS X 10.7 Lion

Main article: OS X Lion

OS X 10.7 Lion was released on July 20, 2011. It brought features from Apple's iOS, like an easy way to see installed applications called Launchpad and more use of multi-touch gestures, to the Mac. This version removed Rosetta, so it could not work with PowerPC programs.

Changes to the interface included auto-hiding scrollbars that only show when needed, and Mission Control which brings together Exposé, Spaces, Dashboard, and full-screen applications. Apple also changed applications: they save in the same state they were in before closing, like iOS. Documents save automatically.

OS X 10.8 Mountain Lion

Main article: OS X Mountain Lion

OS X 10.8 Mountain Lion came out on July 25, 2012. It was the first of the yearly updates to OS X (and later macOS), matching the yearly iOS updates. It added some features from iOS 5, like Game Center, support for iMessage in the new Messages app, and Reminders as a to-do list separate from iCal (renamed Calendar, like the iOS app). It also added support for storing iWork documents in iCloud. Notification Center, a desktop version like the one in iOS 5 and higher, appeared in Mountain Lion. Pop-up messages for applications are now shown in the corner of the screen, and the Center itself comes from the right side. Mountain Lion also added Chinese features including Baidu as a search engine option for Safari, QQ, 163.com and 126.com services for Mail, Contacts and Calendar, Youku, Tudou and Sina Weibo for sharing.

Starting with Mountain Lion, Apple software updates (including the OS) are available through the App Store. This replaced the Apple Software Update tool.

OS X 10.9 Mavericks

Main article: OS X Mavericks

OS X 10.9 Mavericks was released on October 22, 2013. It was a free update for users running Snow Leopard or later with a 64-bit Intel processor. Changes included adding the iOS-only Maps and iBooks applications, improvements to Notification Center, updates to several applications, and many improvements under the hood.

OS X 10.10 Yosemite

Main article: OS X Yosemite

OS X 10.10 Yosemite came out on October 16, 2014. It had a new design like iOS 7, with a simpler, text-based 'flat' look, using translucency and strong saturated colors. Apple's main new feature in Yosemite is Handoff, which lets users with iPhones running iOS 8.1 or later answer calls, receive and send messages, and finish emails started on their iPhone on their Mac. As of OS X 10.10.3, Photos replaced iPhoto and Aperture.

OS X 10.11 El Capitan

Main article: OS X El Capitan

OS X 10.11 El Capitan was released on September 30, 2015. Like Mac OS X 10.6 Snow Leopard, Apple said this version focused on "improving the Mac experience" and "making the system faster". Improvements included public transport in the Maps app, updates to the Notes app, using San Francisco as the system font for better reading, and System Integrity Protection.

The Metal API, first in iOS 8, was added for "all Macs since 2012". Apple said Metal makes graphics up to 50% faster for everyday programs and up to 10 times faster for games and professional programs.

macOS 10.12 Sierra

macOS 10.12 Sierra was released on September 20, 2016. New features included Siri, Optimized Storage, and updates to Photos, Messages, and iTunes.

macOS 10.13 High Sierra

macOS 10.13 High Sierra came out on September 25, 2017. Like OS X El Capitan and OS X Mountain Lion, High Sierra focused on small updates rather than big new features, with changes to Safari, Photos, and Mail, among others.

The big change under the hood was switching to the Apple File System, made for the solid-state storage in most new Mac computers.

macOS 10.14 Mojave

macOS 10.14 Mojave was released on September 24, 2018. It added a system-wide dark mode and several new apps from iOS, like Apple News. It was the first version to need a GPU that supports Metal. Mojave also changed how software updates work from the App Store (since OS X Mountain Lion) to a new section in System Preferences. App updates still use the App Store.

macOS 10.15 Catalina

macOS 10.15 Catalina came out on October 7, 2019. Updates included better voice control, and apps for music, video, and podcasts that replaced iTunes, plus the ability to use an iPad as an external monitor. Catalina stopped supporting 32-bit applications.

macOS 11 Big Sur

macOS Big Sur was announced on June 22, 2020, and released to the public on November 12, 2020. This was the first time the major version number of the operating system changed since the Mac OS X Public Beta in 2000. It added support for Arm processors, new icons, and changes to the user interface.

macOS 12 Monterey

macOS Monterey was announced on June 7, 2021, and released on October 25, 2021. It introduced Universal Control (letting input devices work with multiple devices at once), Focus modes (to limit notifications based on user-defined modes), Shortcuts (a task automation tool like on iOS and iPadOS), a redesigned Safari Web browser, and updates to FaceTime.

macOS 13 Ventura

macOS Ventura was announced on June 6, 2022 and released on October 24, 2022. It brought a redesigned System Preferences (now called System Settings) with an iOS-like design, and new Freeform, Weather and Clock apps that work natively on Mac. Users can use an iPhone as a webcam with Continuity Camera. Siri was updated to look more like on iOS 14 and iPadOS 14. Mail added schedule send and undo send for emails, and Messages got undo send and edit messages. Stage Manager was introduced to organize open windows. Maps got multi-stop routes, Metal 3 added support for improving image quality, Lockdown Mode was added to help prevent cyberattacks, and an option to play ambient background sounds was added for accessibility in System Settings.

macOS 14 Sonoma

macOS Sonoma was announced on June 5, 2023, and released on September 26, 2023. macOS Sonoma changed widgets so they can be placed anywhere on the desktop. Game mode improves game performance by giving games more GPU and CPU power, leading to smoother gameplay. The Spotlight Search bar and all app icons were made more rounded, smoother animations were added for notifications and the lock screen, and new slow-motion screensavers of places around the world were included. When you log in, these slowly change and become your desktop background.

macOS 15 Sequoia

macOS Sequoia was announced on June 10, 2024. It added support for Apple Intelligence features (like a redesigned Siri, writing tools, Image Playground, Genmoji, and system-wide integration with GPT-4o), iPhone Mirroring, a new Passwords app for better password management, and window tiling similar to Microsoft Windows' Aero Snap feature.

macOS 26 Tahoe

macOS Tahoe was announced on June 9, 2025, during the WWDC 2025 keynote. It is the first macOS version to feature the new Liquid Glass design introduced across Apple operating systems that year. It is also the first macOS to use Apple's new release number convention, giving all of Apple's operating systems the same version number. It was released on September 15, 2025.

Security

Apple makes special guides to explain the safety features in macOS and Mac computers.

macOS has extra safety features on Macs with Apple silicon:

• Write xor execute helps stop some safety problems by controlling computer memory.
• Devices like PCIe or Thunderbolt cannot read important memory unless allowed, thanks to IOMMUs.

macOS has a special setting called Lockdown Mode. This mode turns off some features to keep you safer. It stops some website tools from running, blocks unknown FaceTime calls, hides location info when sharing photos, turns off Game Center, and requires approval for accessories. These changes help protect against certain online threats.

Only the newest version of macOS gets all safety fixes. The two versions before that get some fixes, but not all.

macOS Ventura added a quick way to update safety features called Rapid Security Response updates. These updates may need a restart but are very fast. Lockdown Mode is a strong safety setting for people who might be targeted by very advanced online attacks. Apple says most people do not need to worry about these types of attacks.

Malware and spyware

In the past, macOS did not have many problems with harmful software. As more people started using macOS, some harmful software appeared. Later, Apple helped fix the problem and released updates to protect users. Apple regularly updates macOS to keep it safe and includes special tools to find and block harmful software.

Reception

As of January 2023, macOS is the second-most used desktop operating system on the internet, after Microsoft Windows.

Apple promotes macOS mainly to sell Macs. They show updates in Apple Store locations and hold events for developers. Apple has shown in big ads that macOS works well for media and home use.