How to Bulk Migrate Thunderbird to Office 365 Efficiently?

  Rollins Duke
Rollins Duke   
Published: October 23rd, 2025 • 8 Min Read

Overview: If you want to migrate your Thunderbird account data, such as email, calendar, and contacts. This is the right place to understand how you can do it. This blog will cover various methods, reasons, and a specialized approach to convert your Thunderbird to Office 365 email. This approach will guide users to overcome challenges and will show an efficient way to convert Thunderbird to Office 365.

Office 365 Account: Office 365 or Microsoft 365 email account is a cloud-based service provided by Microsoft for education, business, and enterprise needs. It has a custom domain and is powered by Exchange Online.

Thunderbird: Thunderbird is a service provided by Mozilla as a free personal email. Thunderbird stores all your email data in a single file called “mbox”(mailbox) file. That file is stored on your desktop or system locally. Thunderbird doesn’t have cloud features like working on shared documents or shared calendars and scheduling, etc.

Note: This blog methods will only work with the paid service by Microsoft emails and which generally has [email protected]and not on “Outlook.com” or any other emails which are free personal email account and is not considered an Office 365(Microsoft 365) account.

Objectives to Migrate Thunderbird to Office 365

Users want to export Thunderbird to Office 365 for several reasons. Thus, to know the main causes behind that, read the prominent objectives mentioned below:

  • Remote access: Users can access Office 365 email from anywhere worldwide using any computer. It asks only for account credentials.
  • Auto updates: Thunderbird requires constant updating, whereas there is no need to install the latest updates; it always keeps up to date automatically because it is connected to the web.
  • Productivity apps: Office 365 comes with multiple productivity applications that are helpful for growing your business revenue. Like ms word, power BI, exchange online, etc.
  • Advanced security: Office 365 is available with effective pricing, and it provides encryption to keep your email data safe and secure.

Professional Way to Use Thunderbird to Office 365 Migration Tool

Best in the industry, Thunderbird Converter Wizard gives all the freedom to its users to migrate Thunderbird to Office 365, including all email items and attributes. The software has the power to migrate and select Thunderbird data in bulk.

Also, the tool provides a simple and user-friendly interface to all technical and non-technical users. Plus, this Thunderbird to Office 365 migration tool provides dual options to add Thunderbird profile data in the software GUI manually and automatically, which helps in a specific output. Some of the features and working steps of this pro solution are mentioned below in detail:

Brief Guide to Export Thunderbird to Office 365

  1. Run Thunderbird to Office 365 Migration Tool on your system.
    thunderbird to office 365 migration tool
  2. Now, choose the manual or auto way to add Thunderbird profile data.
    add thunderbird profiles
  3. Next, select the required Thunderbird folders and press the Next button.
    select thunderbird folders
  4. Afterward, choose Office 365 from the list of saving options.
    office 365 saving option
  5. Use advanced settings for Thunderbird to Office 365 migration before starting the process.
    advance settings
  6. Thereafter, enter your Microsoft 365 account login details and click on Connect.
    account credentials
  7. The process to migrate Thunderbird to Office 365 is running.
    migrate thunderbird to office 365
  8. Emails have been successfully migrated from Thunderbird to Office 365 account.
    migrate thunderbird to outlook 365
  9. Now, log in to your Microsoft Office 365 account and view imported emails.
    login to office 365

Benefits of Thunderbird to Office 365 Migration Tool

  • Auto File Detection: The software has two options to add Thunderbird profile data automatically from the default storage location.
  • Bulk Migration: Users can also use the Select Files or Select Folders button to manually add Thunderbird data. Allowing users to migrate data from Thunderbird in batches with attachments and complete information.
  • Targeted Data Migration: The tool previews all the folders and subfolders on the screen so that users can select the required data.
  • Direct migration: There is no need to do any import and export process to migrate Thunderbird to Office 365. Users just have to enter the login details of their Office 365 credentials to initiate migration.
  • Maintain Folder Hierarchy: Use the Copy to default folders option if you want to merge the same Thunderbird folders with Office 365 folders. After selecting this option, you will get Thunderbird Inbox Data in Office 365 Inbox folder.
  • Change Language: The change language option allows you to change the email folder name in multiple international languages, such as English, Dutch, French, German, Spanish, Swedish, Norwegian, Italy, and Finnish.
  • Migrate Specific Account: The I am admin option is also helpful to choose a specific user account to migrate Thunderbird to Office 365 account.
  • Advanced Compatibility: The tool is compatible with all the latest Windows and Mac Operating Systems. It is even obtainable with the free demo version.

Manual Way to Export Thunderbird to Office 365

There are two manual ways to migrate Thunderbird to Office 365, and thus to know about them in detail, read the below shared conventional solutions:

Method 1: Using the Drag and Drop Method

  1. First of all, open Thunderbird on your system.
  2. Now, browse and right-click on the Thunderbird email that you want to export.
  3. Further, click on the Save As option and choose .eml files to convert Thunderbird to EML files.
  4. Once done, open MS Outlook on the very same device.
  5. Make sure that Outlook has your Office 365 account configured in it.
  6. Now, drag the saved .eml file and drop that in any desired Outlook folder.
  7. After this, wait for a while so that Outlook data automatically syncs with Office 365.
  8. And, with this, the process to migrate Thunderbird to Office 365 completes successfully.

Consequences: This method may look easy and quick, but it has multiple limitations that restrict user productivity. Some of them are time-consuming, errors due to manual steps, and an unstructured folder hierarchy after export Thunderbird to Office 365.

Read More: Ultimate Guide to Convert Thunderbird to Outlook

Method 2: Export Thunderbird to Office 365 Using IMAP Settings

If the Thunderbird email application is installed on your computer, then you can use this free method to migrate Thunderbird to Office 365. However, this process is a little lengthy as it has 2 different phases to successfully export Thunderbird to Office 365. The method involves to connect Thunderbird to Office 365 with IMAP settings, then dragging and dropping emails from Thunderbird to Office 365.

Phase 1: Configure Office 365 with Thunderbird

  1. Run Thunderbird on your device and click on Settings.
  2. Click on the menu option in the top-right corner.
    add email account
  3. Click on Add Mail Account and select “email” option.
    select email option
  4. After that, enter your “office 365 credentials.
    enter office 365 credentials

  5. Select the “IMAP” option and click on “Continue“.IMAP configuration
  6. Your account will be successfully added to Thunderbird.
    sucessful configuration

Phase 2: Migrate Thunderbird to Office 365

  1. When the Office 365 account gets added in Thunderbird, it will start reflecting the data on the software panel.
  2. Next, right-click on any email and choose the New Folder option.
    create new folder
  3. Further, give it a name and tap on the Select Folder option.
    enter name of the folder
  4. Then, select the emails or folder you want to add to your Office 365 account.
    select email or folder
  5. Now, drag them and drop them in the configured Office 365 account.
    drag and drop emails
  6. At last, log in to Outlook 365 to cross-verify and view Thunderbird mails there swiftly.
    login microsoft 365

Consequences:  This method becomes extremely time-consuming and hectic for bulk Thunderbird to Outlook 365 migration. Additionally this method is extremely complex to understand

Dwarbacks of Manual Approach

  • Complex approach: The method is extremely complex to perform. This may cause data loss and inaccuracies
  • Time-consuming: it is extremely time-consuming. The data migration takes two phases, which may take users additional time and effort to understand and perform.
  • Data inaccuracy: There is no guarantee of data accuracy. The data may change and get lost during the migration
  • No-bulk migration: Users have to repeat the entire process multiple time for each profile. There is no bulk migration support.
Have Questions? Get Answers Now!

1. I am manually trying to configure my Office 365 account with Thunderbird. But I don’t know what server settings will be used, please suggest.

Ans: Use these server settings while configuring Office 365 email address in Thunderbird.

  • Incoming IMAP Server
  • Server Name: outlook.office365.com
  • Server Port Number: 993
  • Incoming POP3 Server
  • Server Name: outlook.office365.com
  • Server Port Number: 995
  • Outgoing SMTP Server
  • Server Name: outlook.office365.com
  • Server Port Number: 587

2. How to migrate Thunderbird to Outlook 365 without Outlook?

Ans: Use the Thunderbird to Office 365 migration tool for completing this task without MS Outlook.

3. I have configured multiple accounts in Thunderbird. Will your software allow me to migrate all accounts to Microsoft 365?

Ans: Yes, select the “I am converting multiple users” option when adding Thunderbird profile data in the software panel. The tool is capable to migrate Thunderbird emails to Office 365 from several configured accounts.

Conclusion

In the above blog post, we have explained the step-by-step process to migrate Thunderbird to Office 365 via 2 different techniques. These are 100% verified methods, we have tested all the above-mentioned approaches in BitRecover Lab before suggesting them to anyone. If you have any other doubts that we have not covered in this blog, feel free to connect with our support team.


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