At UConn, we've recently migrated our email from a local Outlook server to Microsoft's Outlook 365. For some time now, I have been meaning to organize my various work and personal email archives into a uniform, portable archival standard that could be interoperable between Windows and Mac OS clients (and Unix too?). Additionally I wanted to avoid a webmail, cloud-stored solution of this data. On principle and in order to simply continue to maintain my own overall data management chops, I like to more closely control the storage of my written and photographic output and not rely on the cloud for much. Concerning this particular email archiving project, the timing seemed right to finally get on with it.
Beyond its use as a daily email client, MS Outlook is a solid tool that can also be easily employed to harvest email account data from a variety of host servers either through IMAP or POP3 protocols. In fact, it was MS Outlook running on an old PC at home that I initially used to gather my current UConn, previous employer, and two additional personal email accounts under one roof. The resulting data was stored by separate email accounts into discrete .pst data files in MS Outlook on my PC. So far, so good, so I thought.
On my 4 year year old MacBook Pro, I had a copy of Outlook for Mac. I already knew that I could export all of my .pst archive files from the MS Outlook client either by manually copying them to a large thumb drive from their stored locations or by using Outlook's Export wizard:
The question remained, could Outlook for Mac import and render .pst files from a Windows system? After sneaker-netting a single test .pst to the Mac's desktop with the thumb drive, I then tried to import the .pst through Outlook for Mac. Sure enough, things started well...
...continuing on through subsequent Outlook for Mac import wizard steps. And eventually there it was, a Windows-sourced .pst appearing as a real email archive in Outlook for Mac.
This was heady stuff. However, things quickly turned sour. The .pst format wasn't something that one could ping-pong back and forth between OS's as I had hoped. Counter-intuitively Outlook for Mac doesn't support reciprocal .pst export. PST files are a one way street from Windows to Mac versions of the program.
This left me searching for another email format and another software strategy that could possibly be more generic and open-source. The MBOX file format was something that I vaguely remembered reading about on a listserv. So, I decided to take a look at the U.S. National Archives and Records Administration's Format Guidance for the Transfer of Permanent Electronic Records List for Email. And there was MBOX, right beneath PST in NARA's list of Preferred Formats for Aggregations of Email:
This was good. A valid alternative to try. I then thought for a while about what email client software would be able to import, read, and export MBOX while running on both Mac OS and Windows? Thunderbird, a Mozilla.org project, was something that I had heard good things about in the past. According to the literature, it could run on both OS systems and support MBOX import and export (through a plugin). A problem remained, though.
Unfortunately, MS Outlook doesn't directly export to MBOX. However, Outlook for Mac can! But it's not something inherently automated. Then again, my folder structures weren't that hideously nested or complex. I just had a lot of them. So, I went back to my Windows .pst > Mac Outlook sandbox. Luckily I found that the MBOX conversion process isn't difficult. It is just repetitive and can't be done in groupings higher than the individual email folder level. Still all one has to do is simply drag an existing Outlook for Mac email folder into a coherently-named destination folder on the Mac, and the mail folder gets converted to MBOX on the fly. Nice! Here's a split-screen of that process and its result...