Convert Thunderbird MBOX file into MS Outlook PST or Office 365

Mozilla Thunderbird is a freeware email client that stores mailbox data in an MBOX file. There may arise a situation when you need to access Thunderbird data in Microsoft Outlook and Office 365 email clients. However, both these email clients does not support MBOX file. Thus, to move mailbox data from Thunderbird to Outlook or Thunderbird to Office 365 or Microsoft 365, you will need to convert MBOX to PST.

Personal Storage Table (PST) file is an Outlook data file that can be easily imported into Outlook or Office 365 account.

Manually Convert MBOX File into MS Outlook PST or Office 365

The manual procedure to convert Thunderbird MBOX email items to Outlook PST can be categorized into three steps:

In MS Outlook, Open the folder that stores EML files.Next, Select all the EML files and then drag and drop them into an outlook PST folder

You can also create a new folder in PST mailbox to store all the converted EML files. But, keep in mind, you cannot directly export EML file to PST format when Outlook uses an IMAP email account.

• Convert MBOX files to EML
• Transfer EML to Windows Live Mail
• Export emails from Windows Live Mail to Outlook PST

Now let’s discuss the manual Thunderbird to PST conversion process in detail.

Step 1: Convert MBOX Files to EML

The first step requires converting Thunderbird MBOX emails to EML file format, as EML file can be opened in Outlook. To do so, follow these steps:

1. Launch Mozilla Thunderbird app, and open the folder you want be exported.
2. Select an individual email or click Ctrl+A keys to select multiple emails.
3. Right-click the selected emails, and then click Save As to store all the messages in EML format.
4. In Save As Message dialog box that appears, choose the folder where you want to save the converted files, and then click Save.

All the selected MBOX emails will get saved with .eml extension at the desired location.

To know other ways to convert MBOX File to EML, read this: How to Convert MBOX file into EML File?

Step 2: Transfer EML to Windows Live Mail

Once the MBOX files are converted to EML format, the next step is to convert the EML files to any of the email programs – Outlook Express, Windows Mail or Windows Live Mail. Here, we will discuss the procedure to convert EML emails to Windows Live Mail.

Detailed steps are as follows:

1. Launch Windows Live Mail, and select an existing folder or create a folder.
2. In Windows Explorer, open the folder that stores all the EML files.
3. Select all or specific EML files that you need to convert to PST file format from Windows Explorer.
4. Next, drag and drop the selected EML files to the mail folder in the Windows Live Mail.

Now, repeat the drag and drop procedure for every individual folder that needs to be converted.

Step 3: Export Emails from Windows Live Mail to Outlook PST

Now, when all the email messages are imported to Windows Live Mail, export them to Outlook

Note: Before performing this step, make sure that the MS Outlook is installed on the computer. Also, you need to know that any image files embedded within the Windows Live Mail messages will be converted as attachments that might appear empty when you attempt to access them.

Follow these steps to perform Thunderbird export to PST process:

1. Launch Windows Live Mail, click File > Export emails > Email messages.
2. In Windows Live Mail Export wizard that appears, select Microsoft Exchange from the enlisted options, and then click Next.
3. The application will prompt Export Messages dialog box. Click OK to continue.
4. Select Outlook from the enlisted profile names in the Choose Profile dialog box

Note: Usually the Outlook profile is selected by default.

• Once the profile is selected, click OK to continue with the Thunderbird to PST export process.
• Select the folder that needs to be exported to MS Outlook from Windows Live Mail and click OK. The selected mail folder will be moved to specified MS Outlook profile.

To know how to convert Thunderbird MBOX to Office 365, read this: How to convert MBOX to Office 365?

Challenges Involved in Manual Conversion Method

You may successfully convert Thunderbird MBOX to PST files by following the above stated manual procedure. However, the manual conversion process involves the following challenges:

• It is a complicated and time-consuming process.
• It does not ensure data integrity, as the original folder structure of MBOX file may change.
• Converting EML files to Windows Live Mail manually requires repeating the same conversion procedure several times for every individual folder.
• Attachments are displayed as empty after the conversion is completed.

Direct Method to Convert MBOX Files to Outlook PST File Format

Stellar Converter for MBOX is purpose-built to helps users convert Thunderbird MBOX file to PST format in a few simple clicks. Also, the technical edition of the software allows to directly export resultant PST file to Office 365 or Microsoft 365.

Key Benefits of Using Stellar MBOX Converter Tool

• Allows batch conversion of multiple email files from Thunderbird to Outlook mailbox.
• Converts all the MBOX file components to PST file in their original, intact state.
• Allows exporting all messages along with attachments.
• Supports multiple file saving formats like RTF, HTML and PDF.
• Besides Thunderbird, the software allows conversion of mailboxes from Eudora, Opera, Entourage, AppleMail, Spicebird, Pocomail and other email clients to PST. 

Conclusion

Though you can manually convert Thunderbird MBOX file into MS Outlook PST or Office 365 or Microsoft 365 format, maintaining data integrity can be a challenge. Essentially, the manual Mozilla Thunderbird export to PST process can help you export email items, but the original folder structure of Thunderbird mailbox may be different. Also, the manual process doesn’t support converting other mailbox items such as contacts, calendar, notes, etc.

Use a specialized MBOX to PST converter utility such as Stellar Convert for MBOX to convert Thunderbird mailbox to PST, preserving the original folder structure. The utility also helps export all the mailbox items from Thunderbird email client to Outlook. Also, by using the technician version of the software allow to directly export thunderbird to Office 365 or Microsoft 365.

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About The Author

Eric Simson

Eric Simson is an Email Platform Consultant and is associated with Stellar Data Recovery from last 6 years. He writes about the latest technology tips and provides custom solutions related to MS Outlook, MS Exchange Server, Office 365, and many other Email Clients & Servers.