How to Export MBOX From Thunderbird
In short: To export MBOX from Thunderbird, use the free ImportExportTools NG add-on to write any folder to an MBOX file. You can also copy the folder’s file straight out of your Thunderbird profile, since Thunderbird already stores each folder as MBOX, so there is no conversion. For a whole account in one pass, a tool exports every folder at once.
Thunderbird already stores mail as MBOX
This one fact makes the whole job easier than it sounds. Thunderbird does not keep your mail in a private format that needs converting. It stores each folder as an MBOX file, sitting in your profile on disk. Your Inbox is one MBOX file, Sent is another and so on, inside the Mail and ImapMail directories under the profile. So exporting to MBOX is really just getting those existing files out cleanly, either tidily through an add-on or by copying the file itself. One thing to check first: a newer Thunderbird can be set to store mail as Maildir, one file per message, instead of MBOX. Open Settings then General then Config Editor and look at the message store type. Or just use the add-on below, which writes a proper MBOX either way.
Senior Analyst, Corbett Software
“The trick most guides miss is that Thunderbird already keeps every folder as an MBOX file in your profile. There is no conversion, you are just getting an existing file out. The add-on does it tidily, the profile copy is fastest and a tool is for when you want the whole account in one go.”
Export a folder with ImportExportTools NG
The free ImportExportTools NG add-on is the clean way to export, because it names the file properly and lets you choose where it goes.
- In Thunderbird, click the menu, choose Add-ons and Themes and install ImportExportTools NG.
- Restart Thunderbird if asked, then right-click the folder you want.
- Choose ImportExportTools NG, then Export folder to save it as an MBOX file.
- To include everything beneath it, pick the option to export the folder with its subfolders.
- Choose a destination, then the folder is written out as a .mbox file.
Copy the MBOX file from the profile
Because the folders are already MBOX files, you can copy them out directly, with no add-on.
- Close Thunderbird so the files are not in use.
- On Windows, press Windows + R, type %appdata%\Thunderbird\Profiles and press Enter. On a Mac, open ~/Library/Thunderbird/Profiles in Finder.
- Open your profile, then the Mail or ImapMail folder, then find the file named after your folder, such as Inbox, with no extension.
- Copy that file wherever you want, then add a .mbox extension if the destination program expects one.
This is fastest when you know exactly which folder you want. The trade-off is that the files have no extension and sit among cryptic companion files, so a large account gets fiddly.
Export a whole account at once
The free routes are happiest one folder at a time. For a whole mailbox with many folders, exporting each by hand or matching profile files by name becomes a chore, so a tool does it in one clean pass.
The Corbett Thunderbird Tool auto-detects your profile and exports the whole account to MBOX in one run, every folder named correctly and the structure kept. It previews the mail first, filters by date or sender so you export only what you need, then can also save to PDF or EML if your plans change. A free demo edition runs on every edition of Windows.
- Install and open the tool, then click Open, choose Desktop Email Clients and select Thunderbird.
- Let it detect the profile and preview your folders.
- Click Export, choose MBOX, apply any date or sender filter, then Save. The originals stay untouched.
What to do with the MBOX file
Once you have the MBOX, it is portable. Import it into Apple Mail or another Thunderbird install. You can also feed it to a converter when the destination needs a different format. Our guides cover the common next steps: how to import an MBOX into Thunderbird and how to export Thunderbird emails to PDF. To turn the MBOX into an Outlook PST or a PDF archive, a MBOX converter does it in one step.
Frequently asked questions
Does Thunderbird store emails as MBOX files?
Yes. Thunderbird saves each mail folder as an MBOX file in your profile, under the Mail or ImapMail directory, so exporting to MBOX needs no conversion. A newer Thunderbird can be set to use Maildir instead.
How do I export MBOX from Thunderbird for free?
Install the free ImportExportTools NG add-on, right-click the folder and choose Export folder to save it as MBOX. You can also close Thunderbird and copy the folder file straight from the profile.
Where is the Thunderbird MBOX file located?
Under %appdata%\Thunderbird\Profiles on Windows. On a Mac it is ~/Library/Thunderbird/Profiles, inside your profile in the Mail or ImapMail folder. Each file is named after the folder, usually with no extension.
Can I export all Thunderbird folders to MBOX at once?
ImportExportTools NG can export a folder with its subfolders, but a whole multi-account mailbox is faster with a tool that reads the profile and exports every folder together, named and structured.
What is Maildir and does it change the export?
Maildir is an alternative store where each message is a separate file rather than one MBOX per folder. If your Thunderbird uses it, the add-on still writes a proper MBOX on export, so the steps do not change.
Will exporting change my Thunderbird mailbox?
No. Every method here copies the mail out and leaves the originals in place, so your Thunderbird profile stays exactly as it was.