Turning a ZIP into something that opens itself

The idea behind a self extracting archive is plain enough: compressed data and a small unpacking program are bound into one executable, the recipient double clicks it, a familiar Windows dialog appears, a folder is chosen and a button finishes the job. This tool does exactly that and nothing more: it does not create the ZIP in the first place, it converts an archive that already exists. The scenario the vendor describes is equally specific, and it is distribution to people who have no archiver installed and no interest in learning what a compressed format is. They get the contents without first going to find a utility.

Two shapes: a plain package and an installer

Two kinds of file come out of the tool. The standard package only unpacks, and after unpacking it can open a chosen file and hand it to whichever program the system associates with that type. The installer shape is meant for distributing software: when unpacking finishes it launches a setup program, and it accepts executables, command scripts and the vendor's own information files. If the installation has to restart the machine, the temporary files are cleaned up after the restart rather than left behind. Installer packages also bring extra dialog and automation options, while the plain package stays the better choice for simple delivery, since it can open any file type through its association.

A wizard to build it, a command line to script it

Building one is a guided walk: pick the source archive, set the folder it unpacks into, decide whether to split it across volumes, confirm, and the executable appears. A command line is documented as well, so the same step can be dropped into a batch file and repeated. Splitting is designed for removable media, and the vendor recommends the safe arrangement: the executable code and the first slice of data go into the first volume, the remaining volumes hold nothing but data. That way nobody runs a later volume by mistake and gets an error, or worse, a machine that stops responding.

Compression, encryption and appearance

The fourth version added a good deal on the compression side. Jpeg files can be compressed, with the vendor claiming about three quarters of the original size without visible loss; LZMA is supported, along with WavPack for lossless audio; and archives built with the advanced method of the same family can be handled directly. Encryption covers AES with 128 and 256 bit keys, and several methods including PPMd and an enhanced Deflate cover the rest. File names are handled as Unicode, so Chinese and other international characters no longer turn into garbage. The icon can be replaced anywhere from 16 by 16 up to 256 by 256, including the PNG style introduced with the Vista era, and installer packages let the splash screen and the about text be written to taste, with an option to require administrator rights.

Limits worth knowing

The knowledge base lists a set of boundary conditions. If files inside the source archive were compressed with bzip2, xz or the audio method, or if the archive uses the 64 bit extension, meaning more than 65535 files or a single file or the whole archive beyond 4 GB, no self extracting executable can be produced and the attempt fails with a complaint about a missing archive header. The output itself, being an executable, is capped at 2 GB by the format. Code signing is possible on the result, but the signing tool has to be obtained separately. As for the system, the download page covers Windows 10, 8, 7, Vista and XP, and the knowledge base adds that the fourth version also supports Windows 11.

Version and licensing

Version 4 is sold on its own, the installer weighs about 3 MB, a trial and a 30 day refund promise are offered, and using it properly means buying a licence. One change matters: since the twenty ninth release of the main archiver it is no longer bundled, but sold separately, and the cut down edition that used to ship with it could only make plain packages, without the command line or the advanced archive handling. If files have to reach someone with no archiver at all, or software has to go out as a setup, this is a mature and long lived option.