How to Switch from Thunderbird to Outlook [Solved]

Category: Technology

In this blog, we will cover the different solutions that can help you know how to switch from Thunderbird to Outlook. Methods regarding the transfer of emails and contacts will be covered.

Understanding the Incompatibility of Email Formats

In terms of popularity, Mozilla Thunderbird is among the top email clients used by millions of users worldwide. It is a cross-platform application available for Windows, Mac, and Linux. Thunderbird incorporates multiple features like managing multiple email accounts at the same time, powerful message filtering, etc. Its functionality can be further increased with the help of add-on/ extensions. Thus, making Thunderbird a flexible, customizable, and efficient to use.

Regardless of what email client you use, all the messages will appear to be the same on each of them. However, in the back-end, the file format in which these emails are stored may completely vary. Thunderbird saves its data in MBOX format, which is impossible to open with Outlook. In fact, Thunderbird makes use of SBD folders for the hierarchical management of files. And that too is incompatible with the Outlook PST format. Also, none of these email applications have any sort of integrated options to carry out the conversion in each other’s mailbox format.

Whenever an email conversion scenario is in question, the task is not to look for the best method, but opt for the method that works best in your case.

The Data Files of Thunderbird: Locating & Extracting

In an email migration scenario, the first and foremost thing to do is to understand where your emails are stored. In the case of Thunderbird, you can do the following to locate all its data files:

  • Run Mozilla Thunderbird

  • Click on Tools on the menu bar.

  • Click on Account Settings and choose the Server Settings tab

  • Scroll down and find the required path in the Local Directory section

Whichever account data you need, you will get it in the Server Settings of that particular email account. Here, you will find the required MBOX files (files with no extension) and SBD folders containing more MBOX files. Keep this path in mind for now. As we will first move the Thunderbird contacts to Outlook which is easier to do. And then discuss methods to transfer emails.

Transferring your Thunderbird contacts to Outlook

While Switching from Thunderbird to Outlook, emails are not the only thing that needs your attention. Your connections stored in the address book are equally important. And for this very reason, we will transfer the contacts first. Fortunately, this process is a straightforward one and does not require mediator tools or applications. The step-wise guide is as follows:

  1. Start Mozilla Thunderbird and click on the Address book button.

  2. Select the Tools option from the menu bar and hit the Export option.

  3. Choose the location to save the contacts and ensure that the file type selected is Comma Separated Values.

  4. Once the contacts are saved, open Microsoft Outlook.

  5. Choose File from the menu bar followed by the Open and Import/Export option.

  6. Now, select Import from another program or file and proceed to the next window.

  7. Here, select the CSV file format i.e., Comma Separated Values (Windows)

  8. Find and import the file that was previously exported by MS Outlook

  9. Choose from the given “duplicate contacts” option as per your requirement.

  10. Select the destination folder in Outlook (selecting Contacts is recommended)

  11. Map the contents of the CSV file with its Outlook counterparts and hit the Finish button.

This is how you can import all your contact lists from Thunderbird to Outlook. Bear in mind that for multiple CSV files, this process will require the repetition of steps.

How to switch from Thunderbird to Outlook- Migrating Emails

There are several methods to carry out Thunderbird to Outlook conversion. Each has its own advantages. Some of these methods are free but are equally complex and takes a long time for completion. While some require you to purchase specialized tools for a quick and loss-free process. Ultimately, it depends on your needs and requirements as to which method will suit you the best.

Ist Solution – Manual Conversion

If your needs are restricted to the conversion of a few Thunderbird emails, it can be achieved manually. In this method, simply open the Thunderbird application, locate the mailbox folder whose emails you want to migrate and start dragging and dropping them into a folder in your desktop. These emails will automatically get saved as EML files. You can save all the messages from the mailbox file using the Ctrl+A key or save only selective data with Shift key combination. Another way is to select the files and choose Save As option after right-clicking on it.

Once the EML files are saved, you will now need to move these files into the Outlook interface. Fortunately, Outlook 2010 and the above versions have the ability to read EML files. To do this, select all the EML files and drag-drop them into the Outlook interface. Make sure to drop them into the middle panel for a successful import. Bear in mind that this method may result in a change in email integrity and takes a lot of time to complete. Since it does not address the key problem – switching from Thunderbird to Outlook since the files used are EML and not PST format.

IInd Solution – Specialized Converter for Thunderbird to Outlook Migration

Comparison with other solutions lead to a single conclusion – specialized converter tools are the most reliable and efficient method for switching from Thunderbird to Outlook. Such utilities replace the mediator file EML by directly converting the Thunderbird data into PST format. Usually, while choosing such software, you should look for quality and accuracy above all. The more user-friendly a software is, the easier it is to work with it.

SysTools MBOX to Outlook converter is a multiformat tool with remarkable conversion speed and a varied set of features. It can adapt to your needs by providing two scanning options in the beginning.

  • The ability to automatically detect all Thunderbird profile data without requiring to add its MBOX files.

  • Plus, if you require to add the MBOX files, you can do so as well, thanks to the flexible import mechanism of the tool.

Other than this, the tool allows both batch and selective conversion. And even provides the complete preview of emails and attachments within its interface. It generates PST in Unicode type, allowing you to import them in all Outlook versions (both 32-bit and 64-bit). It is a well-balanced and affordable tool that keeps the email integrity intact while preserving the Thunderbird folder structure.


Although the migration of Thunderbird contacts can be achieved via the manual method, it does not fare well in case of moving emails. The incompatibility of the email data files and using a mediator file format can result in a long, tedious and risky process. Hence, complete automation is required while switching from Thunderbird to Outlook. Not only will the recommended tool severely decrease the conversion time, but it will also keep the originality of the emails by preserving all its attributes without data loss.