Mailunwrap

About

About Mailunwrap

A small, independent tool for reading the email files that arrive from Outlook.

Who makes it

Mailunwrap is made by ALGD LTD, a company registered in Northern Ireland (NI744090). Email [email protected]. It is not affiliated with, endorsed by or connected to Microsoft.

How it reads email files

The readers for Outlook .msg files (Compound File Binary and the Outlook message layout), winmail.dat (TNEF), compressed RTF and RTF-wrapped HTML were written for Mailunwrap from Microsoft’s published Open Specifications: [MS-CFB], [MS-OXMSG], [MS-OXTNEF], [MS-OXRTFCP] and [MS-OXRTFEX]. Standard .eml and .mbox files are read with postal-mime, and Outlook data files (.pst) with pst-extractor. HTML is cleaned with DOMPurify before it is shown, and then shown in a sandboxed frame that may not run scripts or load anything remote unless you ask for pictures.

Outlook for Mac archives (.olm) aren’t documented by Microsoft. The reader was written for Mailunwrap and checked against archives made by Outlook for Mac 2016 and 16.112, with the open-source olm-convert (MIT) and olm-reader (Apache-2.0) projects read for reference; no code was copied from them. Archives are read a piece at a time with the browser’s own ZIP decompression, so big ones don’t have to fit in memory.

It has been tested against openly licensed sample files from the Apache POI, msgreader and postal-mime projects, plus files written by its own test tools. Email software is endlessly varied, so if a file doesn’t open the way you expect, the sender’s own program is the reliable fallback.

Mailunwrap doesn’t decrypt encrypted email or get around rights protection, and never will.

Licences

  • postal-mime 4.2.0 by Andris Reinman, MIT No Attribution licence.
  • DOMPurify 3.4.17 by Cure53 and contributors, used under the Apache License 2.0.
  • pst-extractor 1.12.0 by Ed Pfromer and contributors (MIT licence), with long (Apache-2.0), buffer, uuid-parse and fflate (MIT), bundled into one file that is only loaded when you open a .pst.
  • Fonts: Fraunces and Instrument Sans, under the SIL Open Font License 1.1, self-hosted.

The full licence texts are in licences.txt.