What is macOS?

Everything you need to know about macOS updates

macOS Catalina on a MacBook Pro

 Apple Inc

macOS is the operating system for Apple’s Macintosh computers. When you use a MacBook, MacBook Pro, an iMac, or a Mac Pro, you’re using macOS to manage your files, run your apps, connect to the internet, and more.

macOS is a continuation of Mac OS X (later called simply OS X, pronounced oh-ess-ten), which was originally released in 2001. It is built on Unix; as such, it shares many “under-the-hood” similarities to Unix and Linux, most notably multi-user support, pre-emptive multi-tasking, access to the system via Terminal, and the like. 

OS X was renamed in 2016 as macOS 10.12 Sierra to match Apple’s other operating systems like iOS, watchOS, and tvOS. 

macOS 10.15 Catalina

Planned release: Fall 2019

macOS Catalina web page on Apple.com
Apple Inc

Announced in June 2019 at WWDC, macOS 10.15 Catalina (named for the island off the coast of California) will be the 16th major release of its computer operating system. It will be the first version of macOS to only support 64-bit applications, as well, and will be released as a free update to all Mac users in September of 2019. It will also feature a new development system called Catalyst, which will allow developers to target both macOS Catalina and iPadOS with the same app. Voice control will continue Apple’s quest to let you control your Mac with your voice, and Sidecar will let you use an iPad as a second screen, à la AirDisplay or AirParrot.

iTunes will be split into three new apps: Music, Podcasts and Apple TV, and you’ll start managing your iOS devices connected to your Mac via the Finder. Find My Mac and Find My Friends will be merged into a new app called Find My. Reminders can now handle attachments and Siri will be a bit smarter about when to notify you. Also, widget app Dashboard will be removed in macOS Catalina.

Key New Features:

  • 64-bit applications only
  • Catalyst apps
  • Sidecar iPad second screen
  • iTunes breakup
  • “Find My” app

macOS 10.14 Mojave

Released: September 24, 2018

macOS Mojave desktop

macOS 10.14, or Mojave, was initially announced in June of 2018 at WWDC and released on September 24th that same year. Named for California’s Mojave Desert, macOS 10.14 brought iOS apps Apple News, Voice Memos, and Home to the Mac desktop. It also included a better dark mode and was the last version of macOS to support 32-bit applications (users get a notification when attempting to use these, however). The Finder got a new view for file metadata as well as a new Gallery View to browse your files visually. When you take a screenshot, the image will appear briefly in the corner of your screen, similar to iOS. macOS Mojave also added video capability to its screenshot tool. 

Mojave includes Group FaceTime, which lets you chat with up to 32 people at once using video or audio from your Mac, iPhone, iPad, or even your Apple Watch. Apple’s native web-browser, Safari, added tracking protection and sends less information about your system to websites. It also can create strong passwords for new online accounts, and will store them and autofill forms with them. The Mac App Store was rebuilt with a new interface and editorial content, bringing it right in line with the iOS App Store. There’s a new Discover tab in there, along with Create, Work, Play, and Develop tabs for easier app discovery. News, Stocks, Voice Memos and Home (for HomeKit automation) apps came over from iOS with this release, as well. 

Key New Features:

  • Four iOS apps came to Mac
  • Improved dark mode
  • Gallery view
  • Group FaceTime
  • Mac App Store improvements

Released: September 25, 2017

macOS High Sierra in the App Store
Tatsuo Yamashita / Flickr / CC By 2.0

Named for the High Sierra mountain region in California, macOS 10.13 was the 14th release of macOS. It was the sequel of sorts to the previous OS, Sierra (10.12), offering various performance and technical updates rather than focusing on a complete overhaul. Apple replaced the HFS Plus file system with a new Apple File System, which supported various technologies like 64-bit inode numbers and flash memory to speed up common file-related tasks like duplicating, finding, and backing up files. The low-level graphics API Metal got its second release as Metal 2, which added virtual reality and machine learning features and support for external graphics cards. 

A few more first-party apps got updates as well, with Photos getting an updated sidebar, new editing tools, and the ability to sync photos with tagged People in them with iOS 11. Mail got a new Spotlight search called Top Hits, along with a 35% improvement in storage space. Safari added machine learning to block third party trackers and could now block autoplay videos. Reader mode could also finally be set to on permanently. The Notes app got support for tables and users could now pin notes to the top of their list, while Siri gained a more natural voice along with a machine-learning boost to its artificial intelligence. 

Key New Features:

  • Apple File System
  • Metal 2 graphics
  • New Photos features
  • Better storage in Mail
  • Tables in Notes
  • More expressive, smarter Siri

macOS 10.12 Sierra

Released: September 20, 2016

MacBook with macOS Sierra on it
iphonedigital / Flickr / CC By 2.0

macOS 10.12 Sierra, named for the Sierra Nevada region in California, was the first Macintosh operating system named macOS, taking over for OS X El Capitan (also named after a well-known Californian geographical feature). First announced in June, 2016, macOS Sierra came as a free update to El Capitan in September of that same year. It brought a host of features that still exist in macOS today, including the first Desktop iteration of Siri, iCloud Drive with optimized storage, auto-unlock for your Mac, tabbed interfaces for all supporting apps, picture-in-picture mode to let us watch videos while we do other work, the first support for Apple File System, and Night Shift, a function that reduced blue light from your screen during nighttime hours. 

Apps got new features, as well, including improved face recognition and new object and scene recognition for Photos, a feature that powered the new Memories photo groups. Safari got new developer tools that supported extensions connecting with third-party apps, and Apple Pay got web-based buttons in Safari that would let users complete purchases with their iPhone or Apple Watch. Messages got bigger emojis and tapback features, along with the ability to play YouTube videos and preview web links. In addition, the Mac Messages app let users see iOS 10 additions to iMessage, and also allowed them to toggle read receipts on and off per conversation. iTunes got a new For You tab and a lyric feature for its MiniPlayer, while Notes let users share and collaborate on specific Notes. 

Key New Features:

  • Siri on the Desktop
  • iCloud Drive
  •  Picture-in-picture mode
  • Night Shift
  • Apple Pay on the web
  • iMessage integrations