[2] It includes the largest overhaul of the classic Mac OS experience since the release of System 7, approximately six years before.

Mac OS 8 is one of Apple's most commercially successful software releases, selling over 1.2 million copies in the first two weeks.

[2][3] As it came at a difficult time in Apple's history, many pirate groups refused to traffic in the new OS, encouraging people to buy it instead.

[4] Mac OS 8.0 introduces the most visible changes in the lineup, including the Platinum interface and a native PowerPC multithreaded Finder.

Apple intended Copland as a fully modern system, including native PowerPC code, intelligent agents, a microkernel, a customizable interface named Appearance Manager, a hardware abstraction layer, and a relational database integrated into the Finder.

[5] The system was intended to be a full rewrite of the Mac OS, and Apple hoped to beat Microsoft Windows 95 to market with a development cycle of only one year.

With a dedicated team of 500 software engineers and an annual budget of $250 million, Apple executives began to grow impatient with the project continually falling behind schedule.

[5] This ultimately led to Apple buying NeXT and developing Rhapsody which would eventually evolve into Mac OS X in 2001 (now named macOS).

Major changes in this version included the Platinum theme, a Finder which was PowerPC-native and multithreaded, and greater customization of the user interface.

Carbon support requires a PowerPC processor and installation of the CarbonLib software from Apple's website; it is not a standard component of Mac OS 8.1.

Sherlock plug-ins started appearing at this time; these allowed users to search the contents of other websites.

The HTML format for online help, first adopted by the Finder's Info Center in Mac OS 8, was now used throughout.

This palette could be customized in many ways, by removing the window frame and changing the size and layout of the buttons.

It added support to the Mac OS nanokernel to handle preemptive tasks via the Multiprocessing Services 2.x and later developer API.

Mac OS 8.6 improved PowerBook battery life, added Sherlock 2.1, and is faster and much more stable than either version of 8.5.x.

While CNET's initial review of Mac OS 8 was more circumspect,[13] its editorial staff named it one of the best products of 1997 in their year-end roundup.