It is the basis of Apple's current system software for its other devices – iOS, iPadOS, watchOS, and tvOS. The current macOS is preinstalled with every Mac and is updated annually. Developed between 19 after Apple's purchase of NeXT, Mac OS X brought an entirely new architecture based on NeXTSTEP, a Unix system, that eliminated many of the technical challenges that the classic Mac OS faced. The current Mac operating system is macOS, originally named 'Mac OS X' until 2012 and then 'OS X' until 2016. Noted for its ease of use, it was also criticized for its lack of modern technologies compared to its competitors. The system, rebranded 'Mac OS' in 1996, was preinstalled on every Macintosh until 2002 and offered on Macintosh clones for a short time in the 1990s. In 1984, Apple debuted the operating system that is now known as the 'Classic' Mac OS with its release of the original Macintosh System Software.

includes the graphical user interface-based operating systems it has designed for use with its Macintosh series of personal computers since 1984, as well as the related system software it once created for compatible third-party systems. The family of Macintosh operating systems developed by Apple Inc. The original Macintosh System Software and Finder, released in 1984