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Bring your Thunderbird mail into MailCode

5 October 2026 · searched as move thunderbird mail to mac

Thunderbird keeps each folder as one mailbox file. MailCode reads them where they are — subfolders and all — and files each into its local archive as a folder of its own, searchable with the rest of your mail.

How to do it

Find your Thunderbird profile: in Thunderbird, Help ▸ Troubleshooting Information, then the button beside Profile Folder. Local folders are under Mail, IMAP accounts under ImapMail.
Quit Thunderbird, so the files are not changing while they are read.
In MailCode, choose File ▸ Index EML Files…, click Browse… and pick the folder — Mail/Local Folders, say, or one account under ImapMail.
Name the archive folder, leave Keep the folder structure on disk ticked, and click Index →. Each mailbox lands as a folder — Inbox, Sent, Archives / 2025 — under the one you named.

A Thunderbird profile’s folders, indexed with their tree.

An IMAP account’s files hold only what Thunderbird had downloaded for offline use. A message that is in two mailboxes, like Gmail’s Inbox and All Mail, is kept once. Mail already in the archive is skipped, so the import can be run again. In MailCode 1.14.0 importing needs a mail account added first; the next update imports without one.

MailCode is a mail client for Mac and Windows that keeps your mail in a searchable archive on your own disk. Free for 14 days.

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