StuffIt was originally developed in the summer of 1987 by Raymond Lau, who was then a student at
Stuyvesant High School in New York City. It combined the
fork-combining capabilities of utilities such as
MacBinary with newer
compression algorithms similar to those used in
ZIP. Compared to existing utilities on the Mac, notably
PackIt, StuffIt offered "one step" operation and higher compression ratios. By the fall of 1987 StuffIt had largely replaced PackIt in the Mac world, with many software sites even going so far as to convert existing PackIt archives to save more space. StuffIt soon became very popular and
Aladdin Systems was formed to market it (the last
shareware release by Lau was version 1.5.1). They split the product line in two, offering
StuffIt Classic in
shareware and
StuffIt Deluxe as a commercial package. Deluxe added a variety of additional functions, including additional compression methods and integration into the Mac Finder to allow files to be compressed from a "Magic Menu", or seamlessly browse inside and edit compressed files without expanding them using "True Finder Integration". StuffIt was upgraded several times, and Lau removed himself from direct development as major upgrades to the "internal machinery" were rare. Because new features and techniques appeared regularly on the Macintosh platform, the shareware utility
Compact Pro emerged as a competitor to StuffIt in the early 1990s. A major competitive upgrade followed, accompanied by the release of the freeware
StuffIt Expander, to make the format more universally readable, as well as the shareware
StuffIt Lite which made it easier to produce. Prior to this anyone attempting to use the format needed to buy StuffIt, making Compact Pro more attractive. This move was a success, and Compact Pro subsequently fell out of use. Several other Mac compression utilities appeared and disappeared during the 1990s, but none became a real threat to StuffIt's dominance. The only ones to see any widespread use were special-purpose "disk expanders" like
DiskDoubler and SuperDisk!, which served a different niche. Apparently as a side-effect, StuffIt once again saw few upgrades. The
file format changed in a number of major revisions, leading to incompatible updates. PC-based formats long surpassed the original StuffIt format in terms of compression, notably newer systems like
RAR and
7z. These had little impact on the Mac market, as most of these never appeared in an easy-to-use program on the Mac. With the introduction of
Mac OS X, newer Mac software lost their forks and no longer needed anything except the built-in
Unix utilities such as
gzip and
tar. Numerous programs "wrapping" these utilities were distributed, and since these files could be opened on any machine, they were considerably more practical than StuffIt in an era when most data is cross-platform. With the release of OS X Public Beta,
Aladdin Systems released StuffIt 6.0, which ran under OS X. Although it was late to market,
Aladdin Systems introduced the completely new StuffIt X format in September 2002 with StuffIt Deluxe 7.0 for Macintosh. It was designed to be extendable, support more compression methods, support long file names, and support Unix and Windows file attributes. StuffIt X improves over the original StuffIt format and its descendants by adding multiple compression algorithms such as
PPM, and
BWT to
LZW-type compression. It also added a "block mode" option, error correcting "redundancy" options to protect against data loss, and several encryption options. In January 2005,
JPEG compression was added as a StuffIt X compression option (see the related 'SIF Format' below). From the mid-1990s until the 2005 acquisition by
Smith Micro Software, coinciding with the release of
Mac OS X v10.4 "Tiger," StuffIt Expander came bundled with the Macintosh operating system. Although Mac files generally did not use
filename extensions, one of StuffIt's primary uses was to allow Mac files to be stored on non-Mac systems where extensions were required. So, StuffIt-compressed files save the resource forks of the Macintosh files inside them, and typically have the extension . Newer (non-backwards compatible)
Stuffit X-compressed files carry the file extension . Encrypted StuffIt archives created with the now-discontinued
Private File utility will have extensions. StuffIt-compressed
ShrinkWrap disk images will carry or extensions. However, a
Classic Mac OS version of StuffIt is needed to mount the images or convert them to a newer format readable in
macOS.
Smith Micro Software offers free downloads of
StuffIt Expander for Mac and Windows, which expands (uncompresses) files compressed using the StuffIt and StuffIt X format, as well as many other compressed, encoded, encrypted, and segmented formats. The
shareware application
DropStuff permits the compressing of files into the StuffIt X format. The StuffIt and StuffIt X formats remain
proprietary, unlike some other file compression formats, and
Smith Micro Software charge license fees for its use in other programs. Given this, few alternative programs support the format. There was also a "self-expanding" variant of StuffIt files with a extension that runs as an executable. A utility called exists to turn such an executable into a vanilla sit file. == Derivative products ==