How to Convert Thunderbird to Outlook - A Complete Guide

Dec 9, 2023 | By Deepak Singh Bisht

Mozilla Thunderbird is an open-source cross-platform desktop-based email client for Windows, Linux, and Mac. Many organizations and individual users use it as their default email program for sending/receiving emails. It is also known for features like message management, add-ons, themes, and junk filtering. Despite this, many people are migrating email from Thunderbird to Outlook.

In this post, we will discuss the reason behind Thunderbird to Outlook transfer. We will also learn how to convert Thunderbird to Outlook. If you are looking for a simple solution, then this post will be helpful for you. But before we begin, let's first compare Thunderbird and Outlook.

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Mozilla Thunderbird VS Outlook Comparison

Mozilla Thunderbird MS Outlook
Thunderbird is a free email client. To use Outlook, the user must purchase a license key.
Support Windows, MAC, and Unix OS. Support Windows and MAC OS.
It stores all the data in MBOX files. It uses OST and PST files to save the data.
Support IMAP, SMTP, and POP protocols. Support IMAP, SMTP, and POP protocols.
Low-security High security
It does not support the Exchange server. Support Exchange Server.
It does not support any mobile platform. Support Android, iOS, and Windows mobile.
It does not have a scheduling option. Email scheduling available.

Reasons Behind Thunderbird to Outlook Transfer

Outlook is a popular email client developed by Microsoft. It is known for its user interface, high security, fast synchronization, and advanced features. Outlook also supports SharePoint and MS Exchange Server. To get all these benefits, many users migrate Thunderbird to Outlook.

How to Convert Thunderbird to Outlook?

To convert Thunderbird to Outlook, you can use manual methods and Thunderbird to Outlook Converter. Both are very helpful and effective. Here we are going to use both solutions to perform this migration. You can choose any as per your convenience.

Method 1: Import Thunderbird to Outlook using IMAP

There are four parts to this method. You need to have a Gmail account for this method. If you don't have an account, create a new one. To import Thunderbird to Outlook, we need to configure Gmail in Thunderbird. After that, we will configure Gmail in Outlook. To perform this migration, follow the steps below.

Step 1: Enable IMAP Protocol from Gmail

1. Log in to your Gmail account, click on the settings icon, and select the settings option

Gmail setting menu

2. Click on forwarding and POP/ IMAP

Gmail forwarding pop/imap option

3. Enable IMAP option

Gmail enable IMAP option

4. Click on the save changes button.

Gmail save settings

Step 2: Allow less secure apps on Gmail

1. Go to

Allow thunderbird to aceess Google accounts

2. Click on the Security option

Google accounts security option

3. Select less secure app access

Google less secure option for Thunderbird

4. Enable less secure app access option.

enable less security option

Step 3: Configure Gmail in Thunderbird and Import MBOX to Gmail

1. Start Mozilla Thunderbird.

thunderbird home

2. Go to Tools and select Thunderbird Options

thunderbird options menu

3. Click on the Account setting

thunderbird account setting option

4. Click on Account actions

thunderbird account actions

5. Select add mail account option

Add new mail account in thunderbird

6. Fill in your Name, Gmail ID, password and make sure to select remember password and click on Continue

Enter Gmail Account credentials in Thunderbird

7. Select IMAP (remote folders) and click on Done

Select IMAP remote option in thunderbird

8. On the left pane, select your Gmail account

connected Gmail Account in Thunderbird

9. Right-click on Gmail account and create a new folder

Thunderbird create folder option

10. Provide a name and click on the create folder button

Thunderbird create folder

11. Select your Thunderbird account and press Ctrl+A to select all emails

Thunderbird select all email messages

12. Right-click and select Copy

Thunderbird mail copy to option

13. Select Gmail address and select the folder you just created

Move thunderbird mails to gmail folder

14. Check your Gmail folder

Check imported mails from thunderbird to gmail

15. Go to your Gmail account and check the folder

Check Migrated folder in Gmail

16. Click on the folder to verify

Check Migrated MBOX data in Gmail

Step 4: Configure Gmail in Outlook

1. Launch MS Outlook.

Outlook Home

2. Click on the File option.

Outlook file options

3. Click on Account Settings and select Account settings.

Outlook account settings options

4. From the email tab, click on New.

Adding Gmail account in Outlook

5. From add account window, provide your name, enter Gmail id, password, retype the password, and click on the Next button.

Add Gmail credentials in Outlook

6. After validation, you will get a successful screen. Click on the Finish button.

Outlook Gmail successfully configured screen

7. Close Account settings window

Outlook Gmail Additional screen

8. Go to the left pane and click on Gmail address to view the mails.

Outlook Gmail Additional screen

9. Congratulations! You successfully migrate Thunderbird to Outlook.

With the help of this method, you can quickly migrate Thunderbird emails to Outlook. To perform this migration, you must have Outlook and Thunderbird installed on your machine.


Synchronization Delays: There can be delays in syncing large volumes of emails between Thunderbird, Gmail, and Outlook.

Configuration Errors: Incorrect IMAP settings in either Thunderbird or Outlook can lead to failed email migrations.

Folder Structure: Sometimes, the folder hierarchy in Thunderbird may not be perfectly replicated in Outlook.

Method 2: Export Thunderbird emails to Outlook using the Drag and Drop method

In this method, first, we will export Thunderbird emails to EML format. After that, we will import EML files to Outlook. This method is helpful for smaller mailboxes.

Step 1: Export Thunderbird emails to EML

  1. Open Mozilla Thunderbird
  2. Select the mailbox folder
  3. Select emails that you want to export. If you want to select all emails, then use Ctrl+A
  4. Right-click on the selected mail and choose Save As an option
  5. Select the folder where you want to save EML files.
  6. Click on the Save button to start the export process.

Step 2: Import EML files to Outlook

  1. Open MS Outlook
  2. Select the mailbox
  3. Right-click on the selected mailbox and select the New Folder option
  4. Right-click on the selected mail and choose Save As an option
  5. Give the folder a name and click on the folder
  6. Go to EML Folder, select EML files, and start drag and drop them to folder.

This method is simple, but it is only helpful for a small mailbox. When importing a large mailbox, the Email client freezes.


Time-Consuming for Large Mailboxes: This method can be very tedious and impractical for large mailboxes.

Risk of Data Loss: There is a risk of losing some emails during the drag-and-drop process, especially if Outlook or Thunderbird crashes.

Metadata Issues: Metadata like timestamps and email statuses might not be preserved accurately.

If you are looking for a simple way to perform this migration, you can try a third-party Thunderbird to Outlook converter. With the help of this tool, you can convert Thunderbird email to Outlook PST quickly. After that, you can open PST with Outlook.

Method 3: Convert Thunderbird to Outlook using Thunderbird to Outlook Converter

In this method, we are going to use SysCurve MBOX to PST Converter. It is a powerful tool that provides the best way to convert Thunderbird to PST format. With the help of this tool, you can also converts and export Thunderbird emails to EML, MSG, HTML, and RTF format. To export Thunderbird to Outlook, follow the steps below.

  1. Download and install the MBOX to PST Converter.
  2. Launch the software and click on the Browse button to select MBOX files
  3. After the loading process, the tool will quickly load your data and create a complete preview. You can click on any item to see the preview. (Optional)
  4. Click on the Export option and select folders that you want to export.
  5. Choose PST (Outlook data file) and provide a destination path where you want to save PST.
  6. Click on the Export button to start Thunderbird to PST conversion.
  7. Once the process gets complete, click on the Finish button.

After the conversion process, you can open PST with any version of MS Outlook. This method is considered the best way to transfer Thunderbird to Outlook.

Other helpful features

  • Convert Thunderbird to PST, EML, HTML, RTF, MSG, and other file formats.
  • Generate quick preview mode inside the software window.
  • Maintain original hierarchy folder structure.
  • Migrate Thunderbird to Office 365 and Live Exchange Server.
  • Support more than 20 MBOX email clients.
  • Support MBOX, MBX, and MBS file formats.
  • Free Thunderbird to Outlook conversion for the first 20 items.
  • Support all versions of Windows OS, including Windows 10.

Frequently Asked Questions

How do I import local folders from Thunderbird to Outlook?

To import local folders from Thunderbird to Outlook, you can try manual and third-party solutions. Both can perform this task, but manual solutions take a lot of time. On the other hand, Thunderbird to PST converter quickly converts Thunderbird MBOX files to PST format. After that, you can open the converted file with Outlook.

What is the best Thunderbird to Outlook converter?

There are many tools available that convert and export Thunderbird emails to Outlook PST format. But I like SysCurve MBOX Converter. This tool is equipped with all functionality of the Thunderbird to Outlook converter. With the help of this tool, you can convert and export Thunderbird emails to Outlook PST, MSG, EML, HTML, and other file formats. It comes with a free trial version that allows users to export the first 20 items for free.

How do I Convert Thunderbird to PST?

With the help of the SysCurve MBOX to PST converter, you can convert Thunderbird to PST. After the conversion, you can open the resultant PST files with any version of MS Outlook, including 2019, 2016, 2013, 2010, etc.

Can I migrate Thunderbird to Office 365 with this software?

Yes, with the help of this software, you can migrate Thunderbird to Office 365 cloud platform. But this feature is available in Business and Enterprise versions of this software. To perform Thunderbird to Office 365 migration, you can also use SysCurve MBOX to Office 365 Migrator. It is one of the best software that migrates Thunderbird email to Office 365 primary mailbox quickly.

Will my email attachments be migrated along with the emails?

Yes, in all the methods discussed, email attachments should be migrated along with the emails. However, it's always good to verify a few emails post-migration to ensure attachments are intact.

Can I migrate specific email folders instead of the entire mailbox?

Yes, in both the manual methods and when using a Thunderbird to Outlook Converter tool, you can select specific folders for migration. This is useful if you only need to convert certain parts of your mailbox.

Is there a risk of data loss during the migration process?

While all methods aim to preserve data integrity, there is always a minimal risk of data loss, especially with manual methods or if unforeseen errors occur during the process.

How long does the migration process take?

The duration depends on the size of your Thunderbird mailbox and the method chosen. Manual methods can take longer, especially for large mailboxes, whereas Thunderbird to PST Converter tools are generally faster.

The Final Word

Migrating from Mozilla Thunderbird to Outlook can be a significant step towards a more integrated and feature-rich email management experience. While each method of migration - whether it's using IMAP, the drag-and-drop approach, or a dedicated Thunderbird to Outlook converter - has its own set of advantages, it's important to be aware of their potential limitations and prepare accordingly.

Remember, no single method is a one-size-fits-all solution; your choice depends on the size of your mailbox, your technical comfort level, and whether you're willing to invest in third-party software for a smoother transition. Regardless of the method you choose, the goal is to ensure a seamless migration of your emails, contacts, and calendar entries from Thunderbird to Outlook, enhancing your productivity and email management efficiency.

The Author

Deepak Singh Bisht

Deepak Singh Bisht

Content Lead |

Deepak Singh Bisht is a dedicated IT professional with over 9 years of experience, is a key member at SysCurve Software for the last 5 years. His expertise lies in email migration and data recovery, with a focus on technologies like MS Outlook and Office 365. Deepak, who also delves into front-end technology and software development, holds a Bachelor's degree in Computer Applications.

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