Written by Jennifer Walsh. Reviewed for technical accuracy by Shubham Dixit, Independent Expert in Email Forensics and Data File Conversion.
Shubham is an independent external reviewer and not an employee of PCDOTS.
Quick answer. Whether you need to export anything depends on your account. If your Thunderbird mail is an IMAP account, just add the same account in Mailbird and it syncs from the server, nothing to export. For local or POP mail, upload it to an IMAP server first, since Mailbird cannot import local files directly, then Mailbird syncs it in.
On this page
First, where does your mail live?
Before you look for an export button, one question decides everything, and it saves most people the whole job. Is your Thunderbird mail an IMAP account, or is it local? IMAP mail lives on the mail server, and Thunderbird just shows it, so it is not really trapped in Thunderbird at all. Local mail, including old POP accounts and anything under Local Folders, lives only on your computer. Mailbird treats these two very differently, so figure out which you have first, then follow the matching route below. If most of your mail is a normal Gmail, Outlook or work account, it is almost certainly IMAP, and this is going to be easy.
The account type decides your route.
“The word export sends people hunting for a feature they do not need. If the account is IMAP, the mail is already on the server, so you just add that account to Mailbird and it pulls everything down, there is nothing to move. The only real work is with local mail, because Mailbird will not read loose files from your disk. Their own fix is the sensible one, push those local folders up to an IMAP account first, drag them across in Thunderbird, and then Mailbird syncs them like any other mail. A converter only enters the picture if you also want a clean archive of that local mail as EML or PST to keep.” Shubham Dixit, Email Migration reviewer (draft, pending approval)
IMAP accounts, just add and sync
This is the easy one, and it covers most people. Because IMAP mail lives on the server, you do not export anything, you simply add the same account to Mailbird. Open Mailbird, add your email account with the usual address and password, and it connects to the server and syncs your folders and messages straight in. Mailbird can even pull folders and settings automatically when you connect a Thunderbird account. Your mail is in both clients at once, and nothing on your computer had to move. If every account you use in Thunderbird is IMAP, you are already done.
Local mail, upload it to IMAP first
Local mail needs one extra step, because Mailbird does not import local files from your disk directly. The route Mailbird itself recommends is to get that mail onto a server, where Mailbird can sync it. In Thunderbird, make sure you have an IMAP account added, any modern Gmail or Outlook account works, then drag your local folder onto that IMAP account and let it upload, keep Thunderbird open until it finishes. Those messages are now on the server, so when you add the same account to Mailbird, they sync in with everything else. It is the clean, free way to carry local mail across.
Local mail goes up to the server, then Mailbird pulls it down.
Exporting Thunderbird to EML
Sometimes you do not want it in Mailbird at all, you want the messages as files, to archive or to carry somewhere else. Thunderbird handles that free with the ImportExportTools NG add-on. Install it from Thunderbird’s Add-ons manager, then right-click any folder and choose ImportExportTools NG, then Export all messages in the folder, and pick EML for one file per message, or MBOX for the whole folder as a single file. That is also the honest answer to the common question of turning Thunderbird into EML, it is a built-in add-on job, no purchase needed. Worth knowing, Thunderbird already stores your mail as MBOX files inside its profile, so MBOX is the format closest to how it keeps things.
A tool for archives and other formats
If you are moving a lot of local mail, or you want it as a tidy PST for Outlook or PDF for records rather than loose EML, a converter does that in bulk. The PCDOTS Thunderbird Converter reads your Thunderbird profile and exports the mailbox to EML, PST, MBOX or PDF, keeping folders and attachments, and it can also push mail to an IMAP account that Mailbird then reads. It runs on Windows with a free trial of the first twenty-five items per folder. Be clear on what it is for, it does not place mail magically inside Mailbird, Mailbird still reads from the server, so this is for archiving and format changes, not a shortcut past the routes above.
The tool route, for a kept archive or a different format.
The tool follows four short steps.
Step 1. Install and run the software on Windows, then open your Thunderbird profile.
Load the Thunderbird mailbox, choose an output of EML, PST, MBOX or PDF, or an IMAP destination, pick where to save, and start. The steps below map the same flow.
Related reading, our guides to import DBX files to Thunderbird and import Yahoo Mail to Thunderbird. To open the exported files, the free EML viewer reads .eml without any client.
The methods compared
Pick by your account type and what you want at the end.
| Method | Best for | Good to know |
|---|---|---|
| Add the account in Mailbird | IMAP mail | Free, syncs, no export |
| Upload local to IMAP | Local or POP mail | Free, then Mailbird syncs |
| Export to EML, or a tool | An archive or PST | Files to keep, not into Mailbird |
Frequently asked questions
How do I move Thunderbird emails to Mailbird?
If the mail is on an IMAP account, add that account in Mailbird and it syncs. For local mail, upload the folder to an IMAP account in Thunderbird first, then add it in Mailbird.
Can Mailbird import Thunderbird files directly?
No. Mailbird does not read local files from your disk. You upload local folders to an IMAP server, and Mailbird syncs them from there.
How do I convert Thunderbird emails to EML?
Install the free ImportExportTools NG add-on in Thunderbird, right-click a folder, and choose to export the messages as EML files, or as MBOX for the whole folder.
Where does Thunderbird store my emails?
In your Thunderbird profile as MBOX files, one per folder. This is the format a converter reads when exporting to other types.
Do I need a tool at all?
Usually not. IMAP accounts just sync, and local mail uploads to IMAP for free. A tool helps only for bulk archives or converting to PST or PDF.
Will my folders and attachments be kept?
Yes. Syncing an IMAP account preserves folders, and exports to EML, MBOX or PST keep attachments inside each message.
Move it across today
So the path is short once you know your account type. If your mail is IMAP, add the account in Mailbird right now and watch it sync, you are finished in minutes. If it is local, add an IMAP account in Thunderbird, drag your local folders onto it to upload, then add that account in Mailbird. Only pull in a converter if you also want a kept archive as EML or PST. Check whether your accounts are IMAP or local, pick the matching step above, and make the move today.
