The Unarchiver is a proprietary freeware data decompression utility, which supports more formats than Archive Utility (formerly known as BOMArchiveHelper), the built-in archive unpacker program in macOS. It can also handle filenames in various character encodings, created using operating system versions that use those character encodings. The latest version requires Mac OS X Lion or higher. The Unarchiver does not compress files.
A main feature of the Unarchiver is its ability to handle many old, obscure formats like StuffIt as well as AmigaOS disk images in LZH, LZX, and so on. This is credited in its source code to the use of libxad, an Amiga file format library. Ågren also worked to reverse engineer the StuffIt and StuffIt X formats, and his code was one of the most complete open source implementations of these proprietary formats.
- "MacPaw acquires The Unarchiver Mac app, will keep it updated & free". 9to5Mac. 27 July 2017.
- "End User License Agreement (EULA) for MacPaw Products. Disclaimer and Limitations". MacPaw.com. Retrieved 2019-01-04.
- Popescu, George. "The Unarchiver – A Better Way to Decompress Archives". Softpedia. Retrieved 15 September 2016.
- Seff, Jon. "Mac Gems: The Unarchiver is a free, robust file-extraction utility". Macworld. Retrieved 15 September 2016.
- Fenton, William. "The Unarchiver (for Mac)". PC Magazine. Retrieved 15 September 2016.
- "MacPaw/XADMaster is licensed under the GNU Lesser General Public License v2.1". 2018-03-21. Retrieved 2020-06-01.
- "Command line tools". The Unarchiver. Retrieved 2 March 2019.