The first incarnation of MacBinary was released in 1985. The standard was originally specified by Dennis Brothers (author of the terminal program MacTEP and later an Apple employee), BinHex author Yves Lempereur,
PackIt author Harry Chesley, et al. then added support for MacBinary into BinHex 5.0, using MacBinary to combine the forks instead of his own methods. Most
terminal programs and
internet utilities added built-in MacBinary support during this period as well.
Two years later it was updated to
MacBinary II, to accommodate changes in Mac OS. MacBinary II remained compatible with subsequent updates of the operating system for some time. This changed with the release of
Mac OS 8, which necessitated the release of
MacBinary III in 1996.
In the meantime, Apple itself had released the AppleSingle and AppleDouble formats, which serve the same purpose as MacBinary, but correct some problems with it.