However, confusingly all of these drives were labelled identically. Although very similar to the 400-kilobyte drive which newly replaced Apple's ill-fated Twiggy drive in the Lisa, there were subtle differences relating mainly to the eject mechanism. The drive case was designed to match the Macintosh and included the same 400-kilobyte drive (a Sony-made 3 + 1⁄ 2-inch single-sided mechanism) installed inside the Macintosh. Bill Fernandez was the project manager who oversaw the design and production of the drive. However, it did not actually ship until May 4, 1984, sixty days after Apple had promised it to dealers. The original Macintosh External Disk Drive (M0130) was introduced with the Macintosh on January 24, 1984.

Apple produced only one external 3 + 1⁄ 2-inch drive exclusively for use with the Apple II series called the Apple UniDisk 3.5. The Macintosh external drives were the first to widely introduce Sony's new 3 + 1⁄ 2-inch rigid disk standard commercially and throughout their product line. Though Apple had been producing external floppy disk drives prior to 1984, they were exclusively developed for the Apple II, III and Lisa computers using the industry standard 5 + 1⁄ 4-inch flexible disk format.

Later, Apple would unify their external drives to work cross-platform between the Macintosh and Apple II product lines, dropping the name 'Macintosh' from the drives. The Macintosh External Disk Drive is the original model in a series of external 3 + 1⁄ 2-inch floppy disk drives manufactured and sold by Apple Computer exclusively for the Macintosh series of computers introduced in January 1984.

Macintosh floppy emulator