Migrate Thunderbird to Office 365 Manually with Simple Steps

How to migrate Thunderbird to Office 365 platform? If this is the same query in your search then here I will share a manual process of converting data from Thunderbird to Office 365. With this single method, you can export and upload Thunderbird to O365 with all mail & attachments.

We all know that Mozilla Thunderbird stores the data in MBOX and Maildir files format while Office 365 allows importing PST file via Network upload method. So, our first task is to create a PST file form Mozilla Thunderbird.

Method of exporting Thunderbird mailbox into PST

Phase 1: Get ready your Gmail account

  • Gmail Account and click on gear icon.
  • Press “See All Setting” option in open window.
  • Click on “forwarding and POP/IMAP” tab and “Enable IMAP” under IMAP access.
  • Now open a new tab and search “less secure apps”. Select first option “Sign in - Google Account” and ON it.

Phase 2: Create Thunderbird account with Gmail using IMAP protocol

  • Open Mozilla Thunderbird and click on Email under Set up another Account
  • Fill your Gmail account detail and click on continue button. It automatically authenticates it and configure with the Gmail.
  • Now create a new folder under Gmail account in Mozilla Thunderbird and drag all email into new folder which you want to convert into PST format.

Phase 3: Configure same Gmail account with MS Outlook

  • Run Microsoft Outlook >> Go to file tab >> Information >>  Add Account
  • Enter the email address >> Click on Advanced Options.
  • Enable checkbox, I want to set up my account manually option then click connect.
  • Choose IMAP account type and fill the server detail

1.     Account type           IMAP

2.     Incoming mail server-       imap.gmail.com

3.     Outgoing mail server-       smtp.gmail.com

·        Select SSL in the Encryption method list and enter 993

·        In the Outgoing email section, enter port 587.

·        Click on Next button to initiate the configuration.

Note: Fill the same Gmail account detail that you use to open account.

Second Method (Alternative)

This is an alternative choice because it does not applicable on latest version of MS Outlook. Also TB maildir cannot be used in this process.

Phase 1

  • Install and configure Eudora email client and Paste Thunderbird mailbox into Eudora mailbox.
  • Change its extension like XYZ.mbox == XYZ.mbx (These are family formats and store similar pattern of data structure.)

Phase 2

  • Run Microsoft Outlook and go to file tab then select Import-Export Tool.
  • Select “import internet mail & address” then press the next button.
  • Choose “Eudora (2x, 3x, & 4x) pro and light” and next.
  • Browse the destination of Eudora mailbox and again press next.
  • Save the destination where you want to store Thunderbird data then press finish button.

When it is completed you will the get the PST file at your Outlook mailbox location.


By following the above steps, you will get your Thunderbird data in PST file format. Now further we can import PST data into Office 365 using network upload method.

Read here: https://www.itninja.com/blog/view/easily-import-pst-to-office-365-with-simple-migration-steps

If you need a simple and direct solution for Thunderbird to Office 365 migration then you can go through this URL: https://tinyurl.com/2r7h92dd

Conclusion: In this article I have explained the manual methods of importing the Thunderbird data to Office 365 environment. Hoping the information was helpful for you. Please share your feedback in comment.


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