How to Bulk Migrate Thunderbird to Office 365 Efficiently?

Rollins Duke
Published: May 5th, 2025 • 8 Min Read

Various users want to migrate Thunderbird to Office 365 account because nowadays, one thing is clear that the cloud is the future for emails. Hence, users are preferring to use cloud-based online email services instead of desktop email clients and thus, seek a reliable way to export Thunderbird to Outlook 365. 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 intact. Therefore, to make the Thunderbird mail to Office 365 migration process easier, we prepared this complete guide.

Quick Introduction to Case: MBOX is the file type in which Thunderbird saves its email data. Thus, emails, attachments, calendars, and contacts – everything will be available in Thunderbird profile at default storage location. Hence, the agony in the process to migrate Thunderbird to Office 365 is that Office does not have any option to import MBOX files. So, we need to convert Thunderbird file emails to another file type that is supported by Office 365. Using trustworthy, well-performing, and advanced Thunderbird to Office 365 migration tool or manual way, we can convert Thunderbird emails to Office 365 swiftly.

Objectives to Migrate Thunderbird to Office 365

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

Users can access Office 365 email from anywhere 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 that are helpful for growing your business revenue.
Plus, Office 365 is available with effective pricing, and it provides encryption to keep your email data.

Professional Way to Use Thunderbird to Office 365 Migration Tool

Best in the industry, BitRecover Thunderbird Converter Wizard gives all the freedom to its users to migrate 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. 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:

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Brief Guide to Export Thunderbird to Outlook 365

Run Thunderbird to Office 365 Migration Tool on your system.
Now, choose the manual or auto way to add Thunderbird profile data.
Next, select the required Thunderbird folders and press the Next button.
Afterward, choose Office 365 from the list of saving options.
Use advanced settings for Thunderbird to Office 365 migration before starting the process.
Thereafter, enter your Microsoft 365 account login details and click on Connect.
The process to migrate Thunderbird to Office 365 is running.
Emails have been successfully migrated from Thunderbird to Office 365 account.
Now, log in to your Microsoft Office 365 account and view imported emails.

Benefits of Thunderbird to Office 365 Migration Tool

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 just have to enter the login details of their Office 365 credentials to initiate migration.
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 Outlook 365 Inbox folder.
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.
The I am admin option is also helpful to choose a specific user account to migrate Thunderbird to Outlook 365 account.
Thunderbird to Office 365 Migration maintains the folder hierarchy structure while moving data between both email programs. It also preserves all email attributes and attachments.
It has 25+ other file saving options as well, which allow the users to convert Thunderbird to PST, MBOX, MSG, etc., or transfer Thunderbird to Gmail, Yahoo, Maildir, etc.
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 Outlook 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

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

Method 2: Export Thunderbird to Outlook 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 Outlook 365.

Phase 1: Configure Office 365 with Thunderbird

Run Thunderbird on your device and click on Settings.
Now, choose Account Settings and further select Account Actions.
Click on Add Mail Account and fill in the Office 365 email credentials.
After that, if the notification of Configuration found in the Mozilla ISP database comes, then click on Done otherwise, choose the manual configuration option.

Phase 2: Migrate Thunderbird to Office 365

When the Office 365 account gets added in Thunderbird, it will start reflecting the data on the software panel.
Next, right-click on any email and choose the New Folder option.
Further, give it a name and tap on the Select Folder option.
After this, select all the emails that you want to migrate from Thunderbird to Outlook 365.
Now, drag them and drop them in the configured Outlook 365 account.
Wait for a while so that the process to export Thunderbird to Outlook 365 completes.
At last, log in to Outlook 365 to cross-verify and view Thunderbird mails there swiftly.

Consequences: This method won’t work in case of export Thunderbird contacts, calendars, or notes to Office 365 account. Plus, this method becomes extremely time-consuming and hectic for bulk Thunderbird to Outlook 365 migration. In addition to this, there is no folder hierarchy management after the process to export Thunderbird to Outlook 365 completes, which makes the data unorganized and inaccessible when needed.

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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