Having recently switched my e-mail accounts from POP to IMAP (highly recommended!), I wondered what to do with my archived e-mail. With POP everything is stored locally, so the archive was naturally part of the local folders in my Thunderbird installation. With IMAP everything is stored remotely by default, unless moved explicitly to local folders. But independence from specific e-mail clients is one of IMAP’s advantages, and Thunderbird’s future is dubious since Mozilla has demoted the project to maintenance mode. I’m not too happy storing long-term archives in one program’s idiosyncratic databases, either. (Thunderbird uses mboxrd, a modified mbox format.)
The best archive format for e-mail messages is obvious: plain text in MIME format, using the standard extension .eml. This format is very widely supported and stores each message as an individual human-readable file, complete with any metadata and attachments. Exporting messages from Thunderbird to EML files is easy, too. There’s a built-in export facility, but I recommend the powerful Import Export Tools, a Thunderbird extension by Paolo “Kaosmos.” His tools can export entire folders at once, build a convenient HTML index, and start each EML file name with the message date for easy sorting.
The Viewer Wasteland
So we have a simple widespread export format. Surely there’s an abundance of great free viewer applications so we don’t need to reimport our exported messages into an e-mail client just to read them, right? Wrong. Here’s what I found in my quest for an EML viewer application running on Windows.
First the oddball option, discovered by Erik Kangas: simply change the file extension from .eml to .mht and open the file in Internet Explorer. This trick works because IE web archives use the same MIME format as EML files. It’s not terribly useful, though, since attachments are inaccessible.
Michal Mutl’s Mail Viewer is a compact free program that requires no installation. Sadly it’s not very powerful: you can only open a single folder at a time (no tree browsing or recursion), there’s no search at all, and the renderer usually screws up formatting. By the way, SoftSpire tries to pass off this exact same program as its own. Michal is aware of the rip-off and is currently negotiating with the company.
Kernel EML Viewer is another free option that doesn’t quite work. In this case, the problem is that the embedded viewer tries to launch the Windows EML file association. Maybe that’s fine if you have Outlook Express; on Windows 8 with Thunderbird, all I get is a prompt to view the file in an external Thunderbird window. 2013-07-24: No link because this company’s SEO “expert” reacted to a Google page rank warning by randomly spamming inbound links with removal requests. My links don’t damage anyone’s page rank, but I didn’t want to recommend this product anyway…
SysTools EML Viewer (same here) is the third free option with problems. Here it’s a tiny non-resizable application window that’s virtually unusable. Moreover, the program tries to write log files to its installation folder like it’s Windows 3.1 all over again!
Email Open View Pro is slow, cannot search directory trees, lacks a proper manual, and charges $10 on top of the advertised $20 if you want updates beyond 90 days. The free edition is extremely limited and shows intrusive ads.
Encryptomatic’s commercial viewers top out at an astounding $70 for bulk processing capability. If you don’t need that, PST Viewer Lite is decent enough for $30. It’s still somewhat sluggish and not too pretty, but has no obvious bugs or missing features.
Ultimately, the best EML viewer I found is one that doesn’t directly show EML files at all. MailStore Home is a universal e-mail archiving program that can import & export EML files, directly access e-mail accounts, and read the databases of popular e-mail clients. MailStore Home is free for personal use, slick and snappy, feature-complete with a powerful global search, and apparently bug-free. There’s just one drawback: MailStore requires its own binary message database. So for long-term archival you’d have to maintain two archives: one in the robust plain-text EML format, the other in MailStore’s proprietary format.
And that’s it for my haul. I have been completely unable to find any cross-platform EML viewers, though I may well have missed something in the sea of download sites that all offer the same handful of programs reviewed above. So the choice is to pay $30 for PST Viewer Lite, duplicate the message archive in MailStore Home… or just stick with Thunderbird.
2013-07-24: Having found no wholly satisfying alternative, I wrote my own little EML viewer in JavaFX, called MIME Browser.