How to Convert Thunderbird to Maildir with all Attachments?

  

Published By Jamie Kaler 

Approved By Rollins Duke

Published On July 23rd, 2025

Reading Time 6 Min Read

Are you also looking for a solution to convert Thunderbird to Maildir server? If yes, then you are landing on the right page.  Here we will show you the best and most reliable solution to convert Thunderbird mailbox to Maildir. Thus, there are a lot of users who are done with Thunderbird bulk email saving format, as that puts the data at risk and also increases the chance of corruption.

Therefore, to overcome this issue, users often choose to convert Thunderbird to maildir format as it contains single email messages and keeps the data safe for long-term future use. Hence, to learn the different manual and professional ways for Thunderbird export to Maildir, read and follow the complete guide to the very end.

Introduction to Thunderbird and Maildir

Approximately 20 million people around the world use Mozilla Thunderbird, an open and free cross-platform email application offered in 56 languages and offered in a multitude of configurations. Thunderbird is an email client created by the Mozilla Foundation, that is also responsible for the Firefox web browser and other products.

Maildir server is a message-only email format. More ordered and methodical mailbox data storage. Created by Qmail and utilized by numerous apps including Mozilla Thunderbird. Each receiving email gets its file with its name.

Maildir++, an extension to Maildir, supports mail quotas and sub-folders. Sub-directories in Maildir++ files begin with “.” (e.g., “. Inbox “, “. Drafts ” etc.). Maildir++ files are identical to Maildir files.

Reason to Convert Thunderbird to Maildir

• This file format is secure, and there are very few chances of a file becoming corrupted.
• It is simple to transfer data from one platform to another.
• Excellent message filtering based on the folders in which they are stored.
• By their qualities, all of the messages are saved into the appropriate subfolders.
• Using a structured format, any type of cybercrime may be identified and investigated more quickly and effectively.
• Email search, retrieval, and deletion are all performed in real-time.

Manual Method For Thunderbird Export to Maildir Format

1. Open Thunderbird on your system and click on the menu icon.
2. Choose Settings and select the General tab.
3. Then, scroll down to the bottom and hit the Config Editor button.
4. After this, click on Show All and find “mail.serverDefaultStoreContractID”.
5. Now, double click on the search result to change it into “@mozilla.org/msgstore/maildirstore;1”
6. Once done, restart Thunderbird click on menu icon again.
7. Select Account Settings and click on Server Settings tab from the panel.
8. Now, make sure that MBOX is chosen as the storage option.
9. After this, drag any email and drop it on the maildir folder.
10. Further, install the plugin ImportExportTools NG option.
11. Now, using this plugin, export the email in EML format.
12. And finally, import it in the account which is Maildir-based.

Drawbacks of the Manual Solution

• It is very complex and confusing to follow for a non-tech user.
• Loss of data formatting or alteration is also possible with the manual way.
• This way consumes a lot of user time, effort, and other resources.
• The manual way is not approved by the professionals due to its various limitations.

1. Firstly, install and run the software on your pc to convert Thunderbird to Maildir.
   
2. And then choose the files that software automatically loads from the Thunderbird account, or upload them manually.
   
3. Now, all the data will show on the screen, and check and enable the data that you want to export.
   
4. And then click on the “Select Saving Option” and select the “Maildir” option from the drop-down.
   
5. And then browse the saving location to save the converted file.
   
6. Lastly, click on the Convert icon to start the procedure.
   

As you can see, it is quite straightforward to convert Thunderbird to Maildir. With this software, you may easily and rapidly convert Thunderbird to Maildir. However, if you have any reservations, this software includes a trial edition of the software. To install the free version of Mozilla Thunderbird to Maildir Migrator, simply click on the “download” icon in the toolbar.

Advanced Features of the Professional Tool

• The Thunderbird to Maildir Migrator can convert multiple data sources at a time without any hassle to convert Thunderbird to Maildir.
• Also, this tool can load the data directly from the Thunderbird profile, and users can choose the Thunderbird data manually.
• Easily convert Thunderbird emails, including their header data (to, cc, cc), subject, and other information.
• Holds the hierarchy of folders in Thunderbird and local directories.
• You may easily move Thunderbird emails from orphaned and corrupted data files without the need to install an email client.
• Also, the converted Maildir file is compatible with all servers like Dovecot, SendMail, Exim, Postfix, Qmail, etc.

Conclusion

Finally, as you can see in the preceding section, we covered every stage to convert Thunderbird to Maildir server. In addition, we discussed both the email clients and the reasons for sending emails that were described above. Also in this write-up, we discussed a solution that can be used to transform the Thunderbird profile data quickly and efficiently. I hope you enjoyed reading the post.