To date, two methods have been used to make a personal computer, not offered by Apple, but able to run a Mac operating system: either create a Macintosh conversion or build a Macintosh clone.

Unlike Mac clones that contain little or no original Apple hardware, Mac conversions are essentially modification kits that require the core components of a previously purchased, genuine Apple Mac computer, such as the Macintosh ROM or the motherboard, in order to become a functional computer system.

Macintosh conversion

This places the commercial production of a Mac conversion under the protection of the first-sale doctrine in the U.S. and similar legal concepts in most other countries.

Macintosh conversion

Background

Since the early days of Macintosh computers, manufacturers have sought to fulfill the needs of customers who wanted to have a computer with Mac OS, but with a functionality not provided by Apple’s existing Macintosh (later called Mac) lineup. Companies making Mac conversions start with a previously purchased, genuine Apple Mac computer, and use them in combination with their own manufactured components to assemble their custom Mac solution. Modifications can be as minor as the addition of a touch-sensitive display bezel to an otherwise factory standard iMac to create for example a kiosk system, or as extensive as the complete replacement of a MacBook's laptop enclosure to create a Tablet Mac.

Macintosh conversion

While this business model of aftermarket modification is most commonly used in the car industry, with one of the most famous examples being the Shelby Mustang, a high performance variant of the Ford Mustang, it has been applied with equal success in the Mac market.

Whereas Mac clones typically aim to compete directly with Apple's solutions through lower prices, commercial Mac conversions rely on offering features/solutions not available from Apple, and where the need for that particular Mac solution is high enough to justify the combined cost of the full price of the Mac donor computer plus the price of the conversion kit and labor. Commercially successful Mac conversions were discontinued when Apple introduced products with competing features.

Legality

By definition, a Macintosh conversion is an aftermarket modification of a previously purchased, genuine Apple Mac computer or laptop, while preserving the core components required to run the Mac operating system, such as the donor Mac's motherboard. Retaining the core Mac computer inside the Mac conversion avoids any of the copyright misuse, DMCA or Mac operating system licensing issues that forms the basis of the legal threat unlicensed Mac clone manufacturers have to face.

The performance of aftermarket modifications is in the U.S. protected by the First-sale doctrine and similar legal concepts in most other countries. Its legality has been tested through litigation, most notably in the automotive industry, where automobile manufacturers have attempted to hinder or suppress automotive aftermarket businesses by means of copyright and/or patent infringement lawsuits.

The application of the aftermarket process makes for a critical legal distinction between Macintosh conversions and Macintosh clones. Whereas none of the Mac conversions of the companies listed below have seen legal action, Psystar, an unlicensed Mac clone maker, was sued by Apple in federal court within months of the introduction of their first Mac clones.

Companies

The following companies have created commercially available Mac conversion solutions:

Axiotron, Inc. Axiotron, Inc., was founded as a Delaware corporation in 2005 with headquarters in Los Angeles, California. It was acquired in 2008 by the publicly traded Toronto, Canada-based Axiotron Corp. (TSX-V: AXO) and dissolved in 2010. The company was the first Mac conversion manufacturer to create a pen-enabled tablet Mac computer.

Notable products include: Modbook – the first true Tablet Mac, this Mac conversion was based on the polycarbonate white MacBook and featured a pen-enabled, but not finger-touch-sensitive screen. The Modbook retained the entire bottom half of the donor MacBook enclosure, only removing the display and the keyboard section, replacing it with the pen-enabled 13.3-inch wide-viewing-angle display in a chrome-plated cast-magnesium bezel. Discontinued in 2010.

Colby Systems, Inc.

Founded in 1982 by Chuck Colby and operating out of Fresno, California, Colby Systems, Inc. launched its first Macintosh portable computer in 1987. In 1991, after introducing but never shipping its final portable Mac solution, the company left the Mac conversion business to work with video technology and was dissolved in 2016.

Notable products include: