The ZIP files they make can be transferred between the two platforms with excellent Is no longer the case in either Windows XP This is most true on the Mac where ZIP was If your version will not, then update to version 7 at the StuffItĪre difficult to work with. Get the StuffIt Expander for any platform. See the note at the bottom of the page to learn about working SITX is merely the newest version of SIT file. SIT files were the standard for years on the Macintosh. SIT files are similar to ZIP files that use a different method of compression. Most file formats can be reduced in size for more efficient use of disk space. The quick answer is that a ZIP file is a container of one or more regular data files in compressed form.