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How to Import MBOX to Thunderbird- Step by Step Guide

Published By Ashwani
Tej Pratap Shukla
Approved By Tej Pratap Shukla
Published On November 17th, 2023

Thunderbird is one of the most popular desktop-based email applications. It is a cross-platform client that offers a wide ways of emailing options to users. Most users look for solutions to import MBOX files to Thunderbird. Because MBOX is a file extension used by various desktop-based email clients like The Bat, Apple Mail, Opera Mail, Entourage, Eudora, Thunderbird, etc to store emails.

In some cases, users have an MBOX file and they need to import it to some application in order to access it. Thus, a user can upload their file into Thunderbird and access all emails stored in it. Now, the question is how it can be done in an efficient manner.

In this article, you will learn how to import MBOX to Thunderbird for free as well as quickly. There are two different ways to achieve this. First is the free method that requires you to install an add-on. while the second method makes use of a professional solution recommended by experts.

Reasons Why Import MBOX into Thunderbird

There are several reasons why users would want to open MBOX files in Thunderbird. Here are some common situations:

  • Users switching email clients that use the MBOX format (such as Apple Mail or Mozilla’s discontinued Eudora) to Thunderbird will need to import their old emails.
  • Sometimes, there is a need to consolidate multiple accounts across different platforms for easier management.
  • Users often back up their emails in MBOX format. So when they decide to import these backups into Thunderbird, they will need to open MBOX file in Thunderbird.
  • Some users prefer Thunderbird due to its features, security, and open-source nature. They might import MBOX files to utilize these benefits.
  • If a user’s current email client is being discontinued or no longer supported, they might export their emails as MBOX files. Then, later import them into Thunderbird to continue using a regularly updated and supported application.

How to Import MBOX Files to Thunderbird on Windows & Mac

Remember: This manual method has a few drawbacks to it which is why experts recommend using a high-end professional tool explained afterward. It will make sure that data is imported safely & no signs of data loss are seen. This guide has been updated to support the latest Thunderbird versions (Works with Thunderbird 115.0 – 115.*).

Phase 1 – Install the Free Add-on in Thunderbird

Thunderbird provides a way to add additional capabilities with the help of extensions/add-ons. One such add-on is ImportExportTools NG which is completely free. It helps in importing MBOX files into Thunderbird for free.

Follow the steps mentioned below to install the free add-on:

  • Launch Thunderbird by navigating to Programs and then Thunderbird.
    open thunderbird email client
  • Click on the Display the Thunderbird Menu icon (3-lines) in Thunderbird.
    display the thunderbird menu
  • Now, click on the Add-ons and Themes option from the dropdown list.
    select add-ons and themes
  • Type “importexporttools” in the search bar, then press the Enter key.
    search for the free add-on
  • In the new window that appears, click on the Add to Thunderbird button corresponding to the ImportExportTools NG button.
    find importexporttools ng
  • Click the Add button to provide permissions to the add-on.
    click add to add the add-on
  • Finally, restart Thunderbird once the add-on is installed successfully.
    restart thunderbird

Now, move on to the next phase to complete the manual process

Phase 2 – Import MBOX Files to Thunderbird for Free

Follow the steps mentioned below:

  • In Thunderbird, right-click on the mailbox (Local Folders) to import the MBOX file.
    right-click on local folders in thunderbird
  • Afterward, a list of options will appear. Here, select ImportExportTools NG >> Import mbox files >> Individual mbox files to start the procedure.
    select importexporttools import mbox file option
  • Then, locate the MBOX file from the location where it is stored on the hard drive.
  • Click on the Open button to import MBOX files to Thunderbird application.
    click on open to select the mbox file
  • The emails are successfully imported into Thunderbird.
    all emails successfully imported from MBOX to Thunderbird

Some Issues Users may face:

  • Thunderbird gets updated on a regular basis, so sometimes the add-on is outdated and does not work on the latest Thunderbird versions.
  • It has been found in some cases that the attachments and images have come out as missing or broken.
  • Some emails have missing header data like subject, to, from, etc.
  • Manual methods are lengthy and time-consuming to perform.

Also Read: How to Import MBOX Files into Microsoft Outlook?

Expert Recommended Method to Open MBOX Files to Thunderbird

In order to overcome the limitations of the manual method, a user is advised to switch to a trusted third-party tool. The Thunderbird Import Wizard software is a widely used application for the same.

For Windows:

Download Now Purchase Now

For Mac:

Download Now Purchase Now

It is an effective and professional solution to import MBOX files in bulk. It allows users to move MBOX files along with their associated email attachments in Thunderbird.

One can also transfer selective emails from the MBOX file using date-range filters. In addition, it is compatible with all the latest Windows OS versions like Windows 11 (64 bit), Windows 10, 8.1, 8, and 7 (32 & 64 bit).

Steps to Importing MBOX File into Thunderbird​

  • Run the software in your system
  • Choose MBOX files/folders to import.
  • Select Thunderbird profile from the given option.
  • Select the All Mails option or Apply Filters.
  • Finally, hit the Import tab to start the process.

The software steps in detail with screenshots are given below:

  • Launch the software on your Windows OS machine. The user interface of the software is as follows:

start thunderbird import tool

  • Now, click the Add Folder button and select the folder containing the MBOX files.

select add folder

  • Once the file is added, the software will display all the MBOX files or folders that you have imported within the software interface, click on Next.

mbox files are added

  • Select the Identity/Account folder in which you want to import the MBOX file.

select thunderbird identity

  • Finally, click on the Import button to upload MBOX files to Thunderbird account.

click import button

  • Click the OK button once the files are uploaded successfully.

files imported successfully

  • Users can view all the imported emails within the Thunderbird email client on the system.

Step 5

After this, you can open MBOX file in Thunderbird and all your emails will get imported to the chosen email client successfully.

User Queries

Let us understand the situation of users who wish to use Thunderbird to open MBOX file mail on Windows OS.

“Hi, I was using Apple Mail in my previous office but now I have changed my job. I have an MBOX of my Apple Mail which I want to transfer to my new email client. I am using Thunderbird in my new office so I urgently want to move my files to Thunderbird. Could someone help me with the same?”

“Hello! I have been using Thunderbird for a long time but recently my system got corrupted so I had to uninstall my old Thunderbird my old MBOX File still exists and I want to import it into my new profile. I am unable to do it so looking for a method. If anyone knows, please suggest.”


Thunderbird is an extensively used email client and MBOX is the standard email file format for many email clients. So, there comes a time when people need to import MBOX files to Thunderbird. The above article clearly states how to open these files in Thunderbird without any hassle.

There are both manuals as well as professional solutions available that one can try. However, due to its limitations and insecure results Manual method is discarded by professionals. So an autonomous application is explained with methods that are easy to follow and self-explanatory.

Frequently Asked Questions

What is ImportExportTools NG?

ImportExportTools NG is an add-on for Thunderbird. It is a free-of-cost add-on that incorporates multiple import and export functionalities in the Thunderbird application. Here, this add-on is used to open MBOX files in Thunderbird.

What does this professional tool do?

This is software that helps you upload MBOX files to Thunderbird application. It is a specialized professional solution that prevents loss of data integrity during the process, unlike the manual method.

Can Thunderbird import MBOX files?

Yes, Thunderbird can easily import MBOX files by using either the professional software that we have discussed above or an add-on (ImportExportTools NG). You can download the add-on from Thunderbird extensions store and the software from its official website.

How do I Import MBOX to Thunderbird manually?

To import MBOX files into Thunderbird, right-click on Local Folders and choose ImportExportTools NG > Import mbox file > Import directly one or more mbox files. Then, select your MBOX file from the system and click on the Open button.

Is ImportExportTools NG able to upload to IMAP configured email account?

To import your MBOX file into the IMAP-configured Thunderbird account, first, upload the file to Local Folders, then use Copy/Move to transfer the uploaded emails to the relevant IMAP-configured account folders. The add-on does not support direct upload into the IMAP account.