StuffIt Expander is a proprietary, freeware, closed source, decompression software utility developed by Allume Systems (a subsidiary of Smith Micro Software formerly known as Aladdin Systems). It runs in Mac OS Classic, Mac OS X, Microsoft Windows, and Linux x86/UNIX.As of November 2010, the latest Macintosh version is 2011 (15.0.2), which requires Mac OS X v10.5 or later.