How to Import MSG Files Into Thunderbird Quickly? Complete Guide

Published By Karen Chard

Approved By Rollins Duke

Published On February 20th, 2026

Reading Time 7 Min Read

Overview: If you have large MSG files to import into Thunderbird, then you are at the right place. In this informative article, we will be learning the best solutions to import MSG files into Thunderbird safely and quickly without any major data loss. In summary, we can basically open MSG files in Thunderbird manually by using Outlook or directly use the automated solution. Let’s move ahead in the blog and see how both methods work.

Many users who have Outlook, most of their emails are saved in MSG file format, like critical documents, attachments, data, etc and the problem starts when Outlook is not available, or it is not licensed. In such cases where it gets difficult to access or share Outlook MSG files, users prefer to shift to an email client that is easily accessible from anywhere and can be shared easily.

Mozilla Thunderbird is a free email client where you can import, save, and export your MSG files into a readable format. Managing files in an email client makes it easier for enterprises, lawyers, IT admins, and every individual. So, let’s see how you can import MSG files into Thunderbird.

How to Import .msg files into Thunderbird? Quick Suggestion

Overall, we have two ways to open MSG files in Thunderbird: either you can use the manual method by importing MSG via Outlook, configuring the same email address in both Thunderbird and Outlook, then drag & drop, or directly use the automated MSG converter. For the manual method, you will need Outlook and Thunderbird to be installed, and the same email address configured in both platforms.

The manual method is not suggested if you have large or sensitive MSG files. On the other hand, you can use the alternative solution if you want to directly import MSG files into Thunderbird without any email client or file size restrictions. Here are both the approaches mentioned below in the blog.

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Manual Methods to Import MSG Into Thunderbird

There is no direct way to open MSG files in Thunderbird manually, as you will have to install Outlook and Thunderbird. On the other hand, you can also configure any email address in both accounts and sync the data. Let’s see the working steps of both approaches.

Manual Method 1: Open MSG in Thunderbird Using MS Outlook

Right-click on the MSG file and choose Open with > Outlook.
After opening the file in Outlook, choose the File option.
Then, choose the Save As option from the drop-down menu.
Select Save as a type like Text Only (*.txt) from the drop-down.
Set a specific destination path and tap the Save button.
Right-click on the TXT file and choose the Rename option.
After that, change TXT to EML extension and click Yes.
See the EML file created for the Thunderbird client.
Run Thunderbird, choose Tools > Add-ons and Themes.
Next, search and add ImportExportTools NG add-ons in Thunderbird.
Right-click on a Thunderbird folder and choose ImportExportTools NG.
Next, select Import EML Messages > Individual EML Messages.
Browse the EML file from your computer and click the Open button.
MSG to Thunderbird import process completed successfully.

Manual Method 2: Import MSG files into Thunderbird via Configuring email address

Configure any email addresses in both Outlook and Thunderbird.
Then, go to Outlook and drag & drop the MSG files into your desired email folder, or create a new one.
Now, wait for Outlook to sync the MSG files and restart both applications.
Then, you may open MSG files in Thunderbird.

Note: This method does not always work. It is a temporary way to view MSG files in Thunderbird. And, there are high chances of data loss in this approach.

Strong Limitations of the Manual Approach

You can see the proper email header information, but this method disturbs the original email body formatting and structure.
Rich attributes in the files, text formatting, headings, hyperlinks, attachments, images, multimedia, etc are not preserved the same as before. Most of the time, attachments get lost.
You will have to import MSG files into Thunderbird one by one, which is very time-consuming and not suitable for professionals.
Outlook is required to be installed and subscribed to.
Large files take a lot of time to sync and open MSG files in Thunderbird. IMAP sync is not made for bulk import. Importing thousands of files is impractical and leads to data loss, or syncing may stop.
Not suitable for lawyers, investigators, or enterprises, as it does not keep the metadata and properties intact.

Automated Way to Import MSG Files Into Thunderbird

As there is no direct manual way to open MSG files in Thunderbird, you can still import large MSG files into Thunderbird directly using the RecoveryTools MSG converter tool. This solution is designed in a way that it can import your large multiple MSG files into the Thunderbird application directly without any errors, data loss, or consuming time.

This tool is fully compatible with both ANSI and Unicode MSG files. Whether you have Windows or Mac, it supports both operating systems despite of their version or edition. Without disturbing the original hierarchy or losing attachments and metadata, it can import your MSGs in bulk. Let’s see the easy working steps of this professional software:

Step-by-Step Guide to Import MSG to Thunderbird

Install the expert converter tool on your device and run it.
Choose the “select files” or ”select folders” option to automatically load the entire MSG mailbox in bulk.
After adding the MSG files, simply select or deselect the files or folders displayed in the original hierarchy.
Select the saving option as Thunderbird and the destination path.
Lastly, hit the Convert button, and you are done.

Prime Features of the MSG to Thunderbird Converter

This is a standalone software and requires no installation of any email client or platform. You can directly import MSG files into Thunderbird easily.
It supports batch conversion of MSG files. You can easily import large MSG files into Thunderbird without worrying about the file size or number of MSGs.
By selecting the main folder, it automatically detects and syncs only the MSG data files, folders, and sub-folders from the scattered data and displays them.
Without losing important data elements, like attachments, links, images, and metadata, are fully intact. Also, the data structure and folder hierarchy remains same after the conversion.
It has an advanced filter option that allows users to specifically import MSG files into the Thunderbird email client with a certain date range or email addresses. You can use the filters like date range, from, to, exclude folders, and many more.

Closing Statement

In the above article, we learned about how we can import MSG files into Thunderbird effectively. If you are a user having just a few MSG files to import, you can use the manual way, which is risky but can work if you have just a few files. But, if you have large MSG files with crucial data, the suitable way is to use the automated solution and open MSG files in Thunderbird securely in bulk. Both ways are explained; it depends on your requirements, whichever method suits you the best.

FAQs and Responses

Q 1: How to open .msg file in Thunderbird?

We have disclosed both the hand-driven manual method and the fully automated professional method to open MSG file with Thunderbird. You can opt for any approach accordingly.

Q 2: Can I import MSG files into Thunderbird by changing file extension?

No, we have tested this technique, but Thunderbird does not support EML file created by changing extensions.

Q 3: Does your software allow batch import MSG to Thunderbird?

Yes, the suggested application is well suitable to bulk open MSG in Thunderbird.

Q 4: Does the MSG to Thunderbird converter work without Outlook?

Yes, this is a standalone tool to open MSG file in Mozilla Thunderbird desktop client.