How to Migrate Thunderbird to Outlook?

To export emails from Thunderbird to Outlook, you would need to convert the MBOX (file used by Thunderbird to store a copy of mailbox items on the system) to PST file (used by Outlook for import/export purposes) beforehand. This is because Outlook doesn't support the MBOX file format. In the following guide, we will see the stepwise process to convert MBOX file to PST format and export the file directly to Outlook by using a professional MBOX to PST converter software. We will also explain a manual workaround to convert the Thunderbird emails to EML format, which can be imported into Outlook.     

What is Mozilla Thunderbird? Why can't Users Directly Migrate to Outlook?

As an open-source email client, users can install Mozilla Thunderbird and use it on their Windows or Mac systems. When an email account is configured, it creates a folder named 'Profiles' on the system's local storage, wherein various user-configured/imported profile folders are present. According to Mozilla, all the mailbox items – emails, contacts, calendars, and more – are stored in the ‘Profile’ folder in MBOX (.mbox) file format.

What is the Location of MBOX File on Windows?

If you want to export Thunderbird to Outlook, you should know the location of MBOX file (which stores the mail items). The application stores the MBOX file at a default location on the system's storage drive. The path is:

C:\Users\\AppData\Roaming\Thunderbird\Profiles

You can also go to the file location from the settings in Thunderbird application. Just click on Help > Troubleshooting Information > Profile Folder > Open Folder.

Why Users Migrate Thunderbird to Outlook?

There are several reasons why users look for ways to move from Thunderbird to Outlook. Some of these are:

• To meet business requirements in case an organization decides to use Outlook instead of Thunderbird.
• Easier emails, contacts, and other mail items access on any device via Outlook on the web app (OWA). Thunderbird only works on the configured device.
• Compared to Thunderbird, which has no built-in collaborative tools, Outlook seamlessly connects with other Microsoft ecosystem services – Teams, OneDrive, Word, Excel, PowerPoint, and others, for improved team collaboration
• Thunderbird does not properly work with Outlook 365 accounts with IMAP and MFA settings enabled. It only works with accounts requiring "Normal Password." In comparison, Outlook can easily work with MFA/IMAP-enabled Exchange or Microsoft 365 accounts.
• Outlook also offers advanced security features, like Multi-Factor Authentication (MFA), Advanced Threat Protection, etc., to safeguard user data and privacy.
• Outlook has a built-in calendar app that can be used for scheduling meeting and appointments.

What are the Methods to Migrate Thunderbird to Outlook?

If you're moving a few emails from Thunderbird to Outlook, the Manual method to save emails as EML files is the way to go. But, if you are an admin and have undertaken the responsibility of transitioning multiple Thunderbird users to Outlook, use an MBOX to PST converter. Let's look at both the workarounds that can help you migrate Thunderbird to Outlook 2021, 2019, 2016, and 2013 in detail.

Method 1: Save Thunderbird Emails to EML Files and Import them into Outlook

An easy way to migrate Thunderbird to Outlook is by saving the Thunderbird emails in EML files and then importing these files into Outlook. However, this is feasible if you need to migrate only a few emails. Here’s how to do so:

Step 1: Save Emails to EML File

• Open File Explorer on your PC and create a new folder to store EML files.
• Open the Mozilla Thunderbird application.
• Hold the Shift key and click on the emails in the Thunderbird mailbox that you want to migrate to Outlook.
• After selecting emails, right click on them and go to Export Messages As > EML Message Format.
• Click on the Messages (Attachments Embedded) option.

• Choose the new folder (created above) and click on Select Folder.
• The selected emails will be saved in EML file format.

Step 2: Import EML Files into Outlook

• Launch Outlook application where you want to import Thunderbird emails.
• Create a new folder (go to the Folder tab and click New Folder).
• Open the folder that contains the EML files.
• Now drag and drop the EML files to the folder that you just created.

Limitations of the Above Method

• It is a time-consuming and repetitive process as you will have to select and save emails from each folder separately.
• Original mailbox hierarchy (folders and subfolders) may be lost when using EML files.
• EML files can only store emails. Migrating contacts, calendars, and other items is not possible.
• The process lacks automation, thus there are high chances of human error.

Method 2: Migrate Thunderbird to Outlook using an MBOX to PST Converter Software

A straightforward way to migrate Thunderbird to Outlook is by using Stellar Converter for MBOX – a DIY desktop application to convert MBOX to PST. This is because this software automates the process and efficiently handles large or multiple MBOX files. The process involves installing ImportExportTools NG add-on in Thunderbird, exporting the mail items to MBOX file, and importing the file contents directly into Outlook. Let’s see how.  

Part 1: Install the ImportExportTools NG Add-on

To export mailbox data to an MBOX file, you need to install the ImportExportTools NG add-on in Thunderbird. Here are the steps:

• Launch Thunderbird on your Windows PC.
• Open Thunderbird Settings by clicking on the Gear icon at the bottom left corner.
• Next, click on the Add-Ons and Themes option.
• It will open Add-Ons Manager in a new tab. Search for the ImportExportTools NG add-on.
• From the results, select the add-on and click on Add to Thunderbird.
• A prompt will appear. Click on Add again.
• After this extension is installed, relaunch Mozilla Thunderbird.

Watch this video to learn how to install the ImportExportTools NG Add-on in Thunderbird.

Part 2: Export Thunderbird Mailbox Data to MBOX File

Now, use this add-on to export mailbox data from Thunderbird. Follow these steps:

• Right-click on a Thunderbird mailbox folder or configured email account. Click on ImportExportTools NG and go to Folder Export (mbox) > As mbox File.

• Choose the destination folder on your system or any connected storage device. Click on Select Folder.

• The selected mailbox folder will be saved as an MBOX file at the chosen file path.

Part 3: Export Thunderbird MBOX File to Outlook

Once you have the MBOX file, use Stellar Converter for MBOX – a specialized MBOX to PST converter tool - to directly export the MBOX file data to Outlook. It is a powerful software that efficiently scans the selected MBOX file and lists all the mailbox items in a tree view structure. Here, you can preview and verify the contents. Then, you can export the data to Outlook PST and various other formats. You can also directly import the Thunderbird data (MBOX) into an Outlook profile.

Here are some highlights of this MBOX to PST converter tool:

• Precise and accurate MBOX to PST conversion
• Save selected mailbox items, like emails, contacts, calendars, tasks, etc.
• Directly export MBOX file to an existing Outlook profile
• Ensures complete mailbox data migration, including contacts and calendars
• Save MBOX file data in other commonly used file formats like EML, MSG etc.
• Apply advanced filters to filter mailbox data based on date range or sender’s email ID
• Auto splits converted large PST file (more than 45 GB)
• Option to exclude Deleted or Spam/Junk items from the exported/converted data
• Intuitive user interface (UI) with easy-to-navigate options
• Supports MBOX files of other MBOX-based email clients, like Eudora, GNU, Google Takeout (Gmail), Apple Mail, and more.
• Directly migrate Thunderbird to a Microsoft 365 account (Technician edition).

Follow the steps below to migrate Thunderbird to Outlook using this tool:

• Download and install Stellar Converter for MBOX on your Windows PC.
• Launch it.
• The Select MBOX window will appear.
• Select the email client (in our case it is Thunderbird) from the Select Mail Client dropdown menu.

• The tool will automatically select the path of the default MBOX file (if Thunderbird is installed).

• After selecting the MBOX file, click on Convert.

• Once the scanning is complete, the software lists all the Thunderbird mail items in a tree-view structure. Select any mailbox item to generate its ‘preview.'

• After verifying the data, select the required items and click on Save Converted File in the ribbon.

• Choose the Export to Existing Outlook Profile option in the Save As window. Click Next.

• The Select MS Outlook profile and PST window will appear.
• Select the Save to MS Outlook Profile radio button.
• A list of user profiles will populate under Profile Name. Select a profile in which you want to export the selected Thunderbird MBOX file items.

• Click on Save.

• You will see the Saving Completed message after the software has exported your Thunderbird mailbox data to the selected Outlook profile.

Manual Workaround vs. DIY MBOX to PST Converter Software

Here is a quick comparison between the manual workaround and the DIY tool

Can I Export Thunderbird to Outlook using a Free Online MBOX to PST Converter?

You can export Thunderbird to Outlook by converting your MBOX file to PST format using a free MBOX to PST converter online by Stellar and then import the file into Outlook. This online converter can quickly convert a single MBOX file of size ≤ 100 MB to PST format for free. It is designed for convenience as it works on any Windows, Mac, or Linux system, via a web browser.

Here are some highlights of this free online utility:

• Instantly convert MBOX to PST in 3 simple steps: Upload > Convert > Download
• Retains the original mailbox folder structure
• Free conversion of an MBOX file ≤ 100 MB in size
• Works via a web browser on macOS, Windows OS, or any Linux system
• Suppo  rts mailbox files of major MBOX-supporting email clients, including Thunderbird, Opera Mail, Eudora, Apple Mail, and more.

After you have successfully converted the MBOX to Outlook-compatible format (PST), you can import this PST file into Outlook using its built-in Import/Export wizard.

Online Vs Desktop – Which version of Stellar Converter for MBOX to Choose?

Here is a comparison of Stellar Converter for MBOX desktop tool and the online converter:

Conclusion

If you want to move a few emails from Thunderbird to Outlook, you can save the required emails as EML files and then drag and drop them into Outlook. However, it is time-consuming, and sometimes, Outlook may not properly display EML files and attachments.

Instead, you can safely import Thunderbird to Outlook using Stellar Converter for MBOX – a professional MBOX to PST converter tool that accurately migrates Thunderbird MBOX file contents to MS Outlook without altering the structure or formatting. Moreover, it can convert MBOX files to PST format, or other commonly used formats like EML and MSG, in a few clicks. This tool supports MBOX files of all popular email clients, including Thunderbird, Apple Mail, SeaMonkey, and Entourage.