Converting Thunderbird Mbox to Outlook PST

Time Of Info By TOI Staff   June 19, 2023   Update on : June 19, 2023

Thunderbird Mbox to Outlook PST

Thunderbird and Outlook are two popular email clients used by individuals and businesses worldwide. Thunderbird, developed by Mozilla, is an open-source email client that stores emails in the Mbox format. On the other hand, Microsoft Outlook is a widely-used email client that stores emails in the Personal Storage Table (PST) format.

Although both Thunderbird and Outlook serve as email clients, they have different file formats for storing emails. Consequently, users who want to switch from Thunderbird to Outlook face the challenge of converting their Mbox files to PST format. In this article, we will provide you with an informative and detailed guide on converting Thunderbird Mbox to Outlook PST manually and with the help of a Mbox to PST converter for maximum efficiency.

Understanding Thunderbird Mbox and Outlook PST Files

Thunderbird Mbox

Mbox is a file format used by Thunderbird to store emails, attachments, and other mailbox data. Mbox files are stored in a single text file, with each message separated by a unique separator called “From_ line.” Thunderbird creates separate files for each folder in the email account, such as Inbox, Sent, Drafts, etc.

Outlook PST

PST stands for Personal Storage Table, a file format used by Microsoft Outlook to store emails, contacts, calendar events, tasks, and other mailbox data. Unlike Mbox, PST files are not simple text files and use a more complex binary format. These files can be password-protected and encrypted, providing better security for sensitive information.

Reasons to Convert Thunderbird Mbox to Outlook PST

There are several reasons why users might want to convert their files from and to each of the formats:

  • Switching Email Clients: Users may decide to switch from Thunderbird to Outlook due to personal preferences or organizational requirements.
  • Compatibility: Outlook does not support the Mbox format, so converting these files to PST is necessary for accessing Thunderbird emails in Outlook.
  • Data Migration: Users may need to transfer their email data to a new computer or share it with colleagues who use Microsoft’s client.
  • Backup: Converting the files is a way to create a backup of important emails that can be accessed using Outlook.

Converting Thunderbird Mbox to Outlook PST: A Step-by-Step Guide

There are several methods available to convert Mbox files to PST, including manual methods and third-party tools. In this guide, we will discuss both approaches.

Method 1: Manual Conversion Using an IMAP Email Account

This method involves using an IMAP-enabled email account to transfer messages from Thunderbird to Outlook. Follow these steps:

  1. Create an Account: If you don’t have one, create an IMAP-enabled email account (e.g., Gmail).
  2. Configure the IMAP Account in Thunderbird: Add the IMAP account to Thunderbird by following these steps:
  3. Go to “Tools” > “Account Settings” > “Account Actions” > “Add Mail Account.”
  4. Enter your name, email address, and password, then click “Continue.”
  5. Thunderbird will automatically configure the IMAP settings. Click “Done” to complete the process.
  1. Transfer Emails from Mbox to IMAP Account: In Thunderbird, drag and drop the emails or folders you want to transfer from your Mbox account to your IMAP account.
  2. Configure the IMAP Account in Outlook: Open Outlook and add the IMAP account by following these steps:
  3. Go to “File” > “Add Account.”
  4. Enter your email address and click “Connect.”
  5. Enter your password and click “Connect” again.
  6. Once the account is configured, click “Done.”
  7. Transfer Emails from IMAP Account to PST: In Outlook, create a new PST file by going to “File” > “Account Settings” > “Account Settings” > “Data Files” > “Add.” Drag and drop the emails or folders from your IMAP account to the new PST file.

Method 2: Using a Third-Party Converter

There are several third-party tools available that can convert Mbox to PST format. These tools offer a more straightforward and efficient conversion process compared to the manual method. To use these tools, follow the steps provided in their respective user guides.

For example, to use OutlookTransfer’s conversion tool you need to have the Mbox file from Thunderbird ready. Then, insert it into the tool and choose the needed format for output. The file you get after that is ready to be used in Outlook.


Converting Thunderbird Mbox files to Outlook PST format is essential for users who want to switch email clients. Although the manual conversion method using an IMAP email account is free, it can be time-consuming and complex. On the other hand, third-party Mbox to PST converter tools provide a faster and more efficient solution. Choose the method that best suits your needs and successfully migrate your email data from Thunderbird to Outlook.

Read more: Converting Thunderbird Mbox to Outlook PST


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