How to Migrate Thunderbird to Office 365 Account?

Rollins Duke   
Published: October 5th, 2023 • 9 Min Read

Various users want to migrate Thunderbird to Office 365 account because nowadays one thing is clear the cloud is the future for emails. Hence, users are preferring to use cloud-based online email services instead of desktop email clients.

The process of Thunderbird to Office 365 Migration or any other email client with emails and attachments is not an easy task. Especially when you are converting your business emails from Thunderbird to Microsoft 365 with all email items and attachments. Read the complete article to migrate Thunderbird email to Office 365.

MBOX is the file type in which Thunderbird saves its email data. Emails, attachments, calendars, and contacts – everything will be available in Thunderbird profile at default storage location. The agony in Thunderbird to Office 365 migration process is that Office does not have any option to import MBOX files.

So, we need to convert MBOX file emails to another file type that is supported by Office 365. Using trustworthy, well-performing, and advanced software we can convert Thunderbird emails to Office 365.

Read Similar: Verified Methods to Export Office 365 Mailboxes to PST

5 Steps to Effortlessly Migrate Thunderbird to Office 365

  1. First, install and run BitRecover Software.
  2. Select Thunderbird mailboxes in GUI.
  3. Choose Office 365 as the destination.
  4. Complete OAuth Authentication using credentials.
  5. Last, click Backup to start migration process.

Using these 5 steps BitRecover makes you compatible to migrate Thunderbird Mail to Office 365 a hassle-free experience. Enjoy the seamless transition to Office 365 and leverage its advanced features for improved productivity and collaboration. Read this article till the end to get complete knowledge about the process.

Why to Migrate Thunderbird Mail to Office 365?

Users want to import mail from Thunderbird to Outlook 365 due to several reasons. Even they know that well Microsoft 365 (formerly Office 365) is suitable for them for business use.

  • Users can access Microsoft 365 email from everywhere worldwide using any computer. It asks only for account credentials.
  • Like Thunderbird, there is no need to install the latest updates, it always keeps up to date automatically.
  • Office 365 comes with multiple productivity applications which are helpful for growing your business revenue.
  • Microsoft 365 is available with effective costing and it provides encryption to keep secure your email data.

#1 Method: Use Thunderbird to Office 365 Migration Tool

Best in the industry BitRecover Thunderbird Converter Wizard gives all the freedom of its users to import mails from Thunderbird to Outlook 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. The tool provides dual options to add Thunderbird profile data in the software GUI manually and automatically. some of the features and working steps are mentioned below in detail:

How to Export Emails from Thunderbird to Office 365?

  1. Run Thunderbird to Office 365 Migration Tool and read migration instructions.
    thunderbird to office 365 migration tool
  2. The tool is capable to add Thunderbird profile data automatically and manually in GUI.
    add thunderbird profiles
  3. Now 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 advance settings according to your need before starting the migration.
    advance settings
  6. Thereafter, enter Microsoft 365 account login details and click on Connect.
    account credentials
  7. The process to migrate Thunderbird email to Office 365 is running.
    migrate thunderbird to office 365
  8. Emails successfully migrated from Thunderbird to Microsoft 365 account.
    migrate thunderbird to outlook 365
  9. Login to your Microsoft Office 365 account and view imported emails.
    login to office 365

Benefits to Use Thunderbird to Microsoft 365 Software

  • The software has two options to add Thunderbird profile data automatically from the default storage location. Users can also use the Select Files or Select Folders button to manually add Thunderbird data.
  • Users can migrate data from Thunderbird in batches with attachments and complete information. Simply the tool previews all the folders and subfolders on the screen so that users can select the required data.
  • There is no need to do any import and export process to migrate Thunderbird to Office 365. Users have just to enter the login details of Office 365 credentials to direct migration.
  • Use 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 Outlook 365 Inbox folder.
  • The change language option allows to change email folder name in multiple international languages such as English, Dutch, French, German, Spanish, Swedish, Norwegian, Italy, and Finish.
  • The I am admin option is also helpful to choose a specific user account to import mails from Thunderbird to Outlook 365 account.
  • Thunderbird to Office 365 Migration maintains folder hierarchy structure during moving data between both email programs. It also preserves all email attributes and attachments.
  • The tool is compatible with all the latest Windows and Mac Operating Systems. Even it is obtainable with the free demo version.

Read Similar: Easiest Way to Migrate IMAP Emails to Office 365

#2 Method: Configure Office 365 Account in Thunderbird

If the Thunderbird email application is installed on your computer, then you can use this free method for Thunderbird to Office 365 migration process. If you are looking for a free technique then go with it. However, this seems like a lengthy process that will be finished after completing mentioned 3 phases.

Phase1: Configure O365 Email ID with Thunderbird

  1. Start the Thunderbird email client and choose Tools.
    start thunderbird
  2. Thereafter, select the Account Settings option from the list.
    account settings
  3. Click on the Account Actions button to continue.
    account actions
  4. Now choose Add Mail Account option as shown in the screenshot.
    add mail account
  5. Set up your existing email addresses, enter Office 365 login details, and click on Continue.
    enter your office 365 login details
  6. Configuration found in Mozilla ISP database, now click on Done. If you are facing any error then choose Configure manually.
    configuration found in database
  7. Enter Microsoft 365 credentials and choose Sign In.
    sign in to your office 365 account
  8. Approval is required to give the required permissions, press the Request Approval button.
    approval required
  9. After that, it will start checking password. Now Verify the configuration using the Admin account.
    checking password

Note: After successfully configuring your Office 365 email address with Thunderbird. Thunderbird will start downloading Office 365 emails. It will take a few hours so please wait for a while.

Phase2: Synch Thunderbird Data with Microsoft 365

  1. Start your Thunderbird and right click on the recently configured account and choose New Folder.
    create new folder
  2. Give a choice name to the folder and click on Create Folder button.
    enter name of folder
  3. Now you can see an email folder is created under a new Thunderbird profile named Thunderbird Emails.
    view new folder
  4. Select all or required emails from a particular folder that you want to migrate from Thunderbird to Outlook 365. Use CTRL+A to select all emails or press CTRL and select required emails.
    select thunderbird emails
  5. Thereafter, drag and drop old Thunderbird emails under the recently created folder.
    drag and drop emails
  6. Here you can see old Thunderbird emails are copying into the newly created folder. Now, wait for syncing all the emails, after that same folder will be created in Office 365 automatically.
    how to export emails from thunderbird to office 365
  7. Log in to your Office 365 account and view Thunderbird emails in a separate folder.
    login to microsoft 365

Note: In this way, anyone can easily migrate Thunderbird to Office 365 account free of cost. Now your task is completed but this is also advisable to remove your Office 365 configured account from Thunderbird for security reasons.

Phase3: Remove Office 365 Account from Thunderbird

  1. Go to Tools >> Account Settings >> Account Actions >> Remove Account option.
    remove account
  2. Are you sure you want to remove the account, also check the “Remove message data” option. Now press the Remove button.
    remove message data
  3. See the popup message “Removal succeeded”, now click on Ok.
    removal succeeded

Some Cons of This Method

  • The lengthy process takes much time.
  • Thunderbird should be installed on your machine.
  • Allows to Migrate Thunderbird to Office 365 from a single folder at a time.
  • Only technical users can successfully perform these steps.
  • Your one wrong operation may become the reason for losing data.

Read Similar: Trusted Ways to Save Email from Office 365 Webmail

#3 Method: Convert Thunderbird Data into O365 Compatible Format

Some users prefer to export Thunderbird emails to PST format because this is the native format of Microsoft. If you also want to convert Thunderbird data into Office 365 compatible format then use Thunderbird to Outlook Converter.

After that, you will need to import PST to Office 365 account which can be possible using PowerShell and Exchange Admin Center (EAC). This technique is also available with limitations.

  • MS Outlook should be installed.
  • Requires knowledge of PowerShell and EAC.
  • Time-consuming and lengthy technique.
  • No guarantee for data loss.
Have Questions? Get Answers Now!

Ques 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:
  • Server Port Number: 993

Incoming POP3 Server

  • Server Name:
  • Server Port Number: 995

Outgoing SMTP Server

  • Server Name:
  • Server Port Number: 587

Ques 2: How to migrate Thunderbird to Outlook 365 without Outlook?

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

Ques 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.


In the above blog post, we have explained step by step process to export emails from Thunderbird to Office 365 via 3 different techniques. These all 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 then feel to connect with our support team.

Read Similar: Migrate Yahoo Email to Office 365: 2 Best Ways