How to Import an MBOX File into Outlook? (2026 Guide – 2 Methods)

You can import your MBOX into Outlook by configuring an IMAP-enabled email account in both the MBOX email client and Outlook – acting as a medium. You can also use a powerful MBOX to PST converter tool to convert this mailbox file to Outlook-importable PST format. After this, just import the resultant .pst into Outlook via the Import/Export functionality.

In this post, we will discuss the stepwise process to convert the MBOX file to PST using a specialized MBOX to PST converter tool and import the PST into Outlook. We will also explore the workaround to import the MBOX file emails into Outlook.

What is an MBOX File?

Introduced with Unix hosts, MBOX (.mbox) is a container file format used by several email clients, including Mozilla Thunderbird, Apple Mail, Eudora, etc. It stores a local copy of the mail items – emails, attachments, contacts, calendars, and more – on the system. Users can easily open it with the help of any supporting email client or a text editor, like MS Notepad, GitHub Atom, etc.

What is a PST File?

PST or Personal Storage Table is a type of file format used by Outlook to store the mailbox items, such as emails, contacts, appointments, journals, etc. It is created automatically when the POP3 account is configured in Outlook or when the user exports the mailbox data. This file is used to move the Outlook mailbox data to another system or import it into another Outlook profile or Office 365 account.

Refer to ‘Open Specifications‘ – an official documentation on PST file format by Microsoft.

Reasons to Import MBOX in Outlook

There are various scenarios in which users try to import MBOX files into Outlook – switching email clients, archiving old mailbox data in Outlook/O365, or more. Listed below are several reasons for this transition:

• When switching from an MBOX-supporting email client, like Thunderbird or Apple Mail, etc., to Microsoft Outlook.
• To consolidate and manage mailbox data from different MBOX-email clients.
• For better integration with MS applications, such as Word, Excel, Teams, and more.
• Open email archives of legacy email clients (such as Eudora or Netscape Mail) that are no longer supported – for long term preservation
• To migrate multiple user profiles from Mozilla Thunderbird or other clients to Microsoft 365, it is a standard practice to convert them to Outlook PST format

Workaround to Import MBOX File Data into Outlook

There is a free way – a manual workaround – you can try to import your MBOX files into Outlook via Thunderbird (as intermediary). The whole process includes these steps:

• Open the archive MBOX file using any supporting email client of your choice (Thunderbird)
• Export the required email messages from it as individual EML files
• Drag and drop the .eml files in Outlook.

Let’s follow the detailed stepwise process below:

Step 1 – Download Mozilla Thunderbird and Create a Profile

First, download and install Thunderbird – a free, open-source email client – on your PC. Then, create a new user profile in it. You can skip this step if you already have it on your PC.

Step 2 – Install ImportExportTools NG in Thunderbird

Now, to import the MBOX file, you’ll need an add-on. Install ImportExportTools NG in Thunderbird. Follow the steps given below:

• Launch the installed Thunderbird client.
• Click on the waffle icon to openthe Thunderbird Menu. Click on Add-ons and Themes.

• In the Personalize Your Thunderbird window, type ImportExportTools NG in the search bar and press Enter.

• Now, select the ImportExportTools NG add-on.

• Click on the Add to Thunderbird button.

• On the next prompt, click on Add to proceed.

• After it is installed, restart Thunderbird

Step 3 – Import MBOX File into Thunderbird and Save Emails in EML Format

With the help of this utility, open your mailbox archive file (.mbox) in Thunderbird and then save the required email messages as EML files. Here’s what to do:

• Launch Thunderbird app.
• Right-click on the Local Folders in the left pane. Select New Folder.

• Name it and click on Create Folder.

• Again, right-click on the newly created folder. Go to ImportExportTools NG > Import mbox Files > Individual mbox Files.

• Select the MBOX file to import into Thunderbird and click Open. You will see all the items after it opens.

• Select all the required email messages, right-click on them, and click on Save As.

• Select the folder to save the email messages and click on Select Folder.

You will see the selected email messages as .eml files in the destination folder.

Step 4: Drag and Drop EML Files in Outlook

Now, move the saved .eml files to Outlook. Follow the steps given here:

• Launch the Outlook desktop application.
• Create a new folder and give it a name.

• Drag and drop the EML files into the newly created folder in Outlook.

Limitations of the Above Process

Though the above workaround can help you import MBOX emails into Outlook, it has certain limitations, such as:

• Exporting large number of emails from an MBOX file as EML files takes a lot of time and effort.
• It is not suitable for moving EML files to Outlook in bulk (500+) as it can result in missing or lost emails.
• Compatibility issues can lead to some imported EML files not opening properly in Outlook.

An Easy and Effective Way to Import MBOX File into Outlook

There is a way to overcome the limitations of the workaround (discussed above) and easily import MBOX data into Outlook without following complicated steps – convert the MBOX file to PST format.

If you have a small MBOX file (less than 100MB in size), you can opt for the free MBOX to PST converter online by Stellar – a specialized web-based utility tool that conveniently converts a single MBOX file to PST, in 3 simple steps: Upload > Convert > Download. It also has a Premium edition that lets you convert five MBOX files of size (≤5GB).

If you want to convert large, multiple MBOX files, of different sizes, you can use Stellar Converter for MBOX – a powerful MBOX to PST converter tool that lets you accurately convert MBOX to PST file format. After conversion, it maintains the original mailbox folder structure and hierarchy, and integrity of mailbox items. It supports 17+ email clients, including Apple Mail, Eudora, Entourage, PocoMail, and Google Takeout. Moreover, unlike the manual EML workaround (explained above), it migrates various mailbox items – emails, contacts, calendars, and tasks – in one process, with no missing items or modifications done to the folder structure.

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

• 100% 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
• Directly migrate Thunderbird to a Microsoft 365 account (Technician edition).

Here are the steps to convert MBOX to PST for Outlook Windows using this DIY tool:

• Download and install Stellar Converter for MBOX on your Windows PC with Outlook installed.
• Launch the software.
• Click on Select Mail Client under the Home tab.

• The Select MBOX window will appear. Select the email client from the Select Mail Client dropdown.

• After selecting the email client, click on either Select File or Select Identity to select the MBOX file. Then, click on Convert.

• The software will start scanning the selected MBOX file. Once the scan is complete, preview the MBOX data.

• Select the mail items you want to save to PST and click on the Save Converted File button under the Home tab.

• Choose the Save As PST option in the Save As window. Click Next.

• Click on Browse to choose the destination folder to save the PST file. Click Save.

Now use the built-in Import/Export feature to open or import the mailbox file into Outlook. Here’s what to do:

• Open Outlook and click on File > Open & Export > Import/Export.

• The Import and Export wizard window will appear. Select the Import from another program or file option and click Next.

• Choose Outlook Data File (.pst).
• Click on Next.

• Click on Browse to choose the converted PST file and then click Next.

• Select the folder in Outlook profile where you want to import the MBOX email items and click Finish.

After the process is complete, you can access the MBOX file items in Outlook.

Manual Method vs MBOX to PST Converter — Which is Better?

The choice of the method to import MBOX file into Outlook depends on your mailbox size, ease of use, and the need to move other mailbox items – contacts, calendars, tasks, etc. Here is a quick comparison between the manual method and Stellar Converter for MBOX.

Use the EML workaround if you are migrating fewer than 100 emails or don’t need contacts or calendars. Stellar Converter for MBOX is apt if you need a complete, reliable migration – including all items – without any limitations.

Common Issues when You Import MBOX to Outlook

Three common issues occur when attempting to import MBOX files into Outlook. Each has a straightforward fix that is easy to follow.

Issue 1: ImportExportTools NG Option is Greyed Out in Thunderbird

Fix: ImportExportTools NG appears to be greyed out when no email account or local folder is configured in Thunderbird application. The add-on requires a mailbox to work.

To add a new email account:

• Go to File > New > Existing Mail Account.
• Add any email account (even a temporary one).
• Then right-click any folder to access the ImportExportTools NG menu.

Issue 2: EML Files Not Opening Correctly in Outlook

Fix: At times, when you import .eml files in Outlook, they do not show the message body, the metadata, or attachments. This usually happens when there are encoding issues. It also happens if Outlook fails to render the HTML code inside the .eml file during a manual drop. You can try to fix this by saving messages in .msg format. You can also ensure that the ‘Messages (Attachments Embedded)’ option is selected during the export. You can avoid these formatting issues by using Stellar Converter for MBOX. Instead of converting to alternative file formats (.eml or .msg), you can use the DIY software to convert the MBOX to PST. After this, all you’d need to do is import the final PST file into Outlook.

Issue 3: PST File Not Appearing After Import in Outlook

After importing the .pst file via the inbuilt Import/Export wizard, the mailbox appears in folder pane under “Outlook Data File”. Look for the imported folder at the bottom of the Outlook folder list in there. If it is still not present, go to File > Open & Export > Open Outlook Data File and manually navigate to the PST file location.

Conclusion

Outlook for Windows doesn’t support the MBOX file format. Hence, you can’t directly import it into Outlook. To import MBOX file into Outlook, you must either use the manual EML workaround or convert the MBOX file to PST format using Stellar Converter for MBOX – a specialized software that facilitates complete mailbox migrations without any file size restriction. Using it, you import various items, including contacts, calendars, and attachments from an MBOX file to Outlook account/s, without altering the folder structure.

Related Guides

How to Import MBOX to Thunderbird?

How to Migrate Thunderbird to Outlook?

How to Import MBOX to Office 365?

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