
I built a free local Thunderbird / mbox → PST converter looking for feedback
Hey everyone,
I’m an MSP technician, and I kept running into the same annoying migration problem: users had years of mail sitting in Thunderbird, Gmail Takeout exports, old POP accounts, exported Local Folders, or random .mbox archives and the path into Outlook / Microsoft 365 was usually either paid closed-source software or awkward Outlook automation.
So I built ContinuMail Converter, a free and open-source Windows tool that converts Thunderbird profiles and .mbox archives into Outlook .pst files.
Repo: https://github.com/ContinuMail/continumail-converter
It converts Thunderbird profiles and standalone .mbox archives into Outlook PST files, locally, without uploading anything or needing Outlook installed.
The big difference: it writes PST files directly with a from-scratch PST engine, instead of using the usual slow Outlook COM automation workaround, or paid SDK's.
t keeps the important stuff: folder structure, HTML bodies, attachments, dates, recipients, threading headers, and Thunderbird state like read/unread, replied/forwarded, starred, junk, and tags where profile metadata is available. Tags become Outlook categories.
I hope someone can find this usefull and i'd appricate all and any feedback.