Thunderbird to Office 365 Migration – Explore the Finest Solution Here!

Written By Ashwani Tiwari
Anuraag Singh
Approved By Anuraag Singh
Published On January 30th, 2024
Reading Time 6 Minutes Reading

No doubt, it is a tedious task to perform Thunderbird to Office 365 migration amongst different users. As we are pretty much aware, Thunderbird is a desktop-oriented email client but provides only basic features for communication purposes.

On the other hand, Office 365 is an online business suite, which renders a bunch of advanced features. Now, when the situation arises to migrate Thunderbird to Office 365, most of the users become panic in search of a reliable and smart solution. Therefore, to mitigate this ever-increasing demand here comes the blog with the best and the smart solution to effectively execute the migration process.

Let’s consider a user-query to transfer Thunderbird to Office 365

“When we started our business, we used Thunderbird application for the purpose of email communication with the intended user. After a couple of years, our business enlarged and so we became a recognized entity. As a result, we are hunting for a smooth and feature-rich email application, which is capable to overcome the minor hurdles faced in Thunderbird email program Upon complete analysis, we came to know that Office 365 is a perfect suite in which we have purchased the complete domain subscription plan. However, we are finding it difficult to initiate Thunderbird to Office 365 migration. Could someone suggest some trustworthy solution to migrate emails from Thunderbird to O365 without facing any kind of data loss failures? Please suggest!”

Get the Best Thunderbird to Office 365 Migration Solutions Here

Here come some proven and reliable workarounds to execute Thunderbird to Office 365 migration process. All you need to do is simply follow the below-mentioned approaches carefully.

Approach #1: Perform Thunderbird to Office 365 Migration – Instant Technique

One can smoothly convert Thunderbird files to Office 365 using the best and top-notch Thunderbird converter tool that help user’s in  MBOX to Office 365 Migration. It is an advanced utility that lets users migrate emails from Thunderbird to Office 365 in bulk using Add File(s) or Add Folder option. Besides normal migration, it also allows exporting the emails by specifying the date range in the given mentioned date range. In addition to that, the software is also capable to maintain the same folder hierarchy of the MBOX file in the Office 365 account.

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  • Completely automatic solution
  • Support Windows 10 & below OS
  • Self-guided with the simple framework
  • Fast and secure migration
  • Do not require the installation of Mozilla Thunderbird


  • Not available for Mac Operating system.

Simple Steps to Migrate Thunderbird to Office 365

  • Step 1: Run Thunderbird to Office 365 migration tool.
  • Step 2: Choose ‘Add Files‘ to import Thunderbird MBOX files.
  • Step 3: Select ‘Office 365‘ as destination.
  • Step 4: Map O365 mailbox with added Thunderbird mailbox.
  • Step 5: Hit ‘Export‘ to finish migration.

There are two ways to enter O365 mailbox ids during mapping. This makes the migration to be performed in two ways:

I. With Impersonation

II. Without Impersonation

Approach #2: Configure Office 365 Account in Mozilla Thunderbird

In case if Thunderbird application is installed on your system, then it’s easy to perform Thunderbird to Office 365 migration. Following are the steps to migrate emails from Thunderbird to O365.

  • Launch Thunderbird application and navigate to Tools>> Account Settings option
  • From the Account Settings wizard, click the Account Actions button from the right-bottom corner and choose Add Mail Account option
  • In the next windows, you need to provide the credentials of the Office 365 account and click Continue to proceed further
  • Now, if you directly hit the Done button, then you will receive an error message. In order to avoid this, click on Manual Config option
  • Next, you need to provide the following details in the new Mail Account Setup window:
    • Incoming: IMAP|| 993| Autodetect
    • Outgoing: SMTP|| 587| Autodetect
  • Once the process is done, hit the Re-test button followed by clicking the Done button to process Thunderbird to Office 365 migration
  • Now, wait until all emails and mail folders of Office 365 get synced with Tbird application
  • After that, just drag the data from Thunderbird profile and drop into O365 folders
  • Repeat the above step until all the emails get transferred from Thunderbird to Office 365 account
  • Now, delete the Office 365 account by clicking on Tools >> Account Settings >> Account Actions >> Remove Account


  • A free of cost solution


  • Only applicable when Thunderbird application is installed
  • It consumes sufficient users’ time and efforts
  • Technical knowledge is required

Approach #3: Convert Thunderbird data & Import into Outlook 365 Account

Users can also convert the Thunderbird data file (MBOX) into an equivalent Outlook PST file. This can be done through manual or automatic techniques. For this, you can go through Thunderbird to PST Converter. After that, import the converted .pst file into O365 via. PowerShell method or Exchange Admin Center. This is a good alternative means to convert Thunderbird to Office 365.



  • Requires introduction of MS Outlook email clients
  • Any mistake in the process leads to data loss or corruption
  • Sufficient amount of time required for this conversion

Let’s Explore Some Frequently Asked Questions By the User

How can I import emails from Thunderbird to Office 365 in a secure way?

With the help of Thunderbird to Office Migrator tool, one can efficiently transfer the Thunderbird mailbox files directly to the Office 365 account in a seamless way.

Is there any free way to migrate Thunderbird files to Office 365 account?

This article defines 3 methods to do so, one of which is completely free.

Is there any reliable way to bulk migration to Office 365?

For users who are looking for a smart and instant way to migrate multiple Thunderbird mailbox files, then one can go for the smart and proven software application.

How to migrate only selective data?

All the 3 given methods have options to migrate only required data. In the manual method, you can select and transfer only the emails that you need in Office 365 account. While the automated tool has dat-range filters to help in migrating only the emails that come within the mentioned dates.

Time to Wind Up

If you are running a business and want to migrate Thunderbird to Office 365, then it is advised to download the third-party solution i.e, Ist Approach. It is an easy-to-use software that migrates emails from Thunderbird to Microsoft 365 in a matter of minutes. Furthermore, it provides a 100% migration rate with no data loss or corruption issues.


By Ashwani Tiwari

Being a Chief Technical Analyst, I am aware of the technicalities faced by the user while working with multiple technologies. So, through my blogs and articles, I love to help all the users who face various challenges while dealing with technology.