How to Export MBOX File From Thunderbird | Save Thunderbird Emails
Thunderbird stores all emails in MBOX format by default. You can export Thunderbird emails to a standalone MBOX file using the free ImportExportTools NG add-on in under 5 minutes. For bulk exports or a GUI-based option, the Turgs Thunderbird Converter handles unlimited folders in one pass.
Thunderbird is free, open-source, and used by millions of people worldwide. Its native file format, MBOX, is one of the most widely supported email archive formats in existence. You can open an MBOX file in Apple Mac Mail, SeaMonkey, Eudora, and dozens of other clients. So when you need to export Thunderbird emails to MBOX, you’re in good shape. The format is already there. You just need to get it out properly.
This guide covers the manual method using Thunderbird’s built-in add-on support, how to locate the raw MBOX files on your system, and a faster automated option for bulk or recurring exports.
What Is an MBOX File
MBOX stands for MailBox. It’s a plain-text container format that stores multiple email messages in a single file. Each message is appended sequentially with a separator line starting with “From “. The format dates back to 1970s Unix mail systems and is still the most widely compatible email archive format available today.
Thunderbird stores your local mail folders as MBOX files on disk. Your Inbox, Sent, Drafts, and every custom folder you’ve created each has a corresponding MBOX file. This means your Thunderbird data is already in MBOX format. The export process is essentially about copying and renaming those files, or using a tool to extract them with proper metadata intact.
How to Export Thunderbird Emails to MBOX
Here are the six steps to export MBOX from Thunderbird using the ImportExportTools NG add-on:
- Launch the solution and open the Thunderbird add-ons manager.
- Add your Thunderbird profile data to the tool.
- Select the folders you want to export as MBOX.
- Choose MBOX as your saving format.
- Apply any filters and choose your destination folder.
- Click Next to start the Thunderbird to MBOX export.
Here is the full walkthrough with screenshots:
Launch Mozilla Thunderbird on your system and click the menu icon at the top right. Choose the Add-ons option from the menu to open the Add-on Manager.
A new window opens. Click the Up and Coming option at the top to browse available add-ons.
In the search field, type “Import/Export” and look for the ImportExportTools NG plugin. Download and install it. Thunderbird will ask you to restart once the add-on installs. Restart it.
Go to your mailbox in Thunderbird and right-click on any folder, such as All Mail or Inbox. Choose the Export Folder option from the context menu.
A file browser dialog opens. Choose the folder where you want to save the exported MBOX file and click OK.
Open your destination folder and find the exported mail file. Right-click it, choose Rename, and add the .mbox extension to the filename. That makes the file universally recognized by other MBOX-compatible clients.
Your Thunderbird emails are now in a portable MBOX file ready to import into any compatible client.
How to Find the Default Thunderbird MBOX Location
You don’t always need the add-on. Thunderbird saves its MBOX files directly on your hard drive. Here’s where to find them depending on your Windows version.
Windows XP / 2000: Open the Run dialog (Win+R) and type %TEMP%. Navigate to the Backup folder, then Thunderbird, then Profiles. Find your profile name folder, open the POP or IMAP subfolder, and you’ll see your INBOX file. Copy it to your desktop and rename it with a .mbox extension.
You can also navigate directly to: C:Documents and Settings[Windows user name]Local SettingsApplication DataThunderbirdProfiles[Profile name]IMAP*.*
Note: Local Settings is a hidden folder. Go to Folder Options, open the View tab, and enable “Show hidden files and folders.”
Windows Vista, 7, 8.1, 10, and 11: Open the Start menu and type %APPDATA% in the search box. Press Enter. In the Windows Explorer window that opens, navigate to Thunderbird, then Profiles. Each folder there is a separate profile.
Direct path: C:Users[Windows user name]AppDataRoamingThunderbirdProfiles[Profile name]
You can also use Thunderbird’s own Help menu: go to Help, then Troubleshooting Information, then click Show Folder to open your profile directory directly.
Automated Solution for Bulk Exports
The manual method works, but it has real constraints. If you need to export dozens of folders at once, or if Thunderbird is corrupted and won’t launch, the add-on approach won’t work. That’s where Turgs Thunderbird Converter fills the gap.
The tool reads your Thunderbird profile folder directly without needing Thunderbird to run. It shows the full folder hierarchy, lets you select exactly which folders to export, and writes the output as clean MBOX files. You can process multiple profiles in one session, which saves hours on large migrations.
If you want to open Thunderbird email data in Outlook later, you’ll need to convert MBOX to PST first. The MBOX Converter Tool by Turgs handles that conversion and supports PST as a direct output option.
Limitations to Know
Limitations
- The manual add-on method requires Thunderbird to be installed and working. A corrupted Thunderbird profile may block the export.
- The ImportExportTools NG add-on exports one folder at a time. Exporting 50 folders individually is time-consuming.
- The raw MBOX file copy method does not export metadata cleanly in all cases. Folder structure may not preserve perfectly.
- The Local Settings and AppData folders are hidden by default on Windows, which confuses less experienced users.
- MBOX files do not store attachments separately. They’re embedded in the file, which can make very large MBOX files slow to open.
- Some email clients require the .mbox extension explicitly. Files without it may not import correctly even if the content is valid MBOX format.
Frequently Asked Questions
Does Thunderbird natively support MBOX export?
Thunderbird stores its data in MBOX format already, but it doesn’t have a native “Export as MBOX” button. You need the ImportExportTools NG add-on to export specific folders as MBOX files, or you can copy the raw files from the Thunderbird profile directory on your disk.
Which email clients can open an MBOX file?
MBOX is one of the most compatible email formats available. Apple Mail, SeaMonkey, Eudora, Entourage, The Bat, Pocomail, and many others can open MBOX files directly. If you need to open the data in Outlook, convert the MBOX to PST format first.
Can I export MBOX from Thunderbird on Windows 10?
Yes. The ImportExportTools NG method works on all current Windows versions including Windows 10 and Windows 11. The profile folder path on Windows 10 is typically C:\Users\[your name]\AppData\Roaming\Thunderbird\Profiles\.
What if my Thunderbird is corrupted and won’t open?
If Thunderbird won’t launch, the add-on method isn’t available. In that case, use a dedicated tool like the Turgs Thunderbird Converter, which reads the profile folder directly from disk without needing Thunderbird to run.
Is there a size limit on MBOX exports from Thunderbird?
The manual method has no explicit size limit, but very large MBOX files over a few gigabytes can take a long time to export and may be slow to open in other clients. Splitting large archives into smaller per-year folders before exporting helps manage file sizes.
How do I verify the MBOX file exported correctly?
Open the exported MBOX file in a text editor like Notepad. Each email should start with a line beginning with “From ” followed by a space and an email address or date. If you see that pattern repeating throughout the file, the MBOX is valid. You can also import it into any MBOX-compatible client to do a visual check.
