How to Open PST File in Thunderbird

Updated on May 28, 2025 by Deepika Singh

Are you planning to switch from Outlook to Thunderbird and want to open PST file into Thunderbird application? If yes, you have landed on the right page. This write-up will provide various methods to import PST files to Thunderbird. Also, we suggest the best solution for PST to MBOX conversion. Let us first learn about Mozilla Thunderbird.

What is Mozilla Thunderbird?

Mozilla Thunderbird is an open-source email client developed by Mozilla Foundation. It is one of the most popular email clients that enables you to manage your emails, contacts, calendars, etc., of multiple email accounts simultaneously. This application is fast, easy to use, and offers numerous features to enhance your productivity and mailing experience.

Why Do I Need to Open PST file into Thunderbird?

Both MS Outlook and Mozilla Thunderbird are popular and advanced email clients. However, many factors lead users to import Outlook mails to Thunderbird email clients. We will share some prominent features of Thunderbird that enable users to manage their mailbox efficiently.

• This email client supports multiple languages. Therefore, you can use this application in any desired language.
• Another recognizable feature of Thunderbird is the enhanced Junk mail filtering that filters out all the malicious and suspicious mail.
• Many platforms like Windows, Mac, and Linux support the Thunderbird email client. Also, it is the default email client for Linux OS.
• The easy-to-use interface is one of the key reasons why users prefer Thunderbird over Outlook or any other email client.

Now, you have learned why users want to export their Outlook mailbox to Thunderbird email client. Let us check different methods to open PST file into Thunderbird.

Also Read: How to Add, Close, and Remove Outlook Data File (PST)?

03 Verified Methods to Import PST Files in Thunderbird

In the manual approach, we use MS Outlook and Mozilla Thunderbird application to migrate Outlook mailbox data to Thunderbird account. This solution is effective and free of cost. Moreover, you can perform this method for any mailbox size. In case the PST file is damaged, you must repair the corrupt or damaged Outlook PST file to perform the steps.

Method 1: Import PST to Thunderbird Manually Using Outlook + Thunderbird (via EML Files)

This method lets you manually export emails from Outlook and import them into Thunderbird by converting them to .eml files.

Step 1: Open Your PST File in Outlook

1. Launch Microsoft Outlook.
2. Go to File > Open & Export > Open Outlook Data File.
3. Browse and select your .pst file.
4. Your PST file will appear as a new folder in Outlook’s sidebar.

Step 2: Create a Folder on Your Desktop

1. Right-click on your desktop.
2. Click New > Folder.
3. Name it something like OutlookEmails – this is where you’ll save the emails.

Step 3: Drag Emails from Outlook to Desktop Folder

1. In Outlook, select one or multiple emails (use Ctrl or Shift to select).
2. Drag and drop them into your OutlookEmails folder.
3. The emails will be saved as individual .eml files.

Step 4: Open Mozilla Thunderbird

1. Launch Thunderbird.
2. (Optional) Create a new folder under Local Folders or your email account to organize the imported emails.

Step 5: Drag & Drop EML Files into Thunderbird

1. Open the OutlookEmails folder on your desktop.
2. Select all .eml files (Ctrl + A).
3. Drag and drop them into your chosen folder in Thunderbird.

That’s it! Your Outlook emails are now accessible in Thunderbird.

Method 2: Import PST to Thunderbird Using IMAP Configuration

This method works by uploading emails from Outlook to an IMAP email account (like Gmail), then syncing that account in Thunderbird.

Step 1: Enable IMAP in Gmail

1. Log in to your Gmail account via browser.
2. Go to Settings (gear icon) > See all settings.
3. Click on the Forwarding and POP/IMAP tab.
4. Under IMAP Access, select Enable IMAP.
5. Scroll down and click Save Changes.

Step 2: Add Gmail Account to Outlook

1. Open Outlook.
2. Go to File > Add Account.
3. Enter your Gmail address and password (or use App Password if 2FA is enabled).
4. Let Outlook configure it as an IMAP account.
5. Once added, you'll see your Gmail account in the folder pane.

Step 3: Move PST Emails to Gmail in Outlook

1. In Outlook, open your PST file
2. Select emails or folders from the PST file.
3. Drag and drop them into your Gmail account folders (e.g., Inbox or create a new folder like "PST Backup").

Outlook will start syncing those emails with Gmail servers. This may take time depending on the size and internet speed.

Step 4: Add the Same Gmail Account to Thunderbird

1. Open Mozilla Thunderbird.
2. Go to Tools > Account Settings > Account Actions > Add Mail Account.
3. Enter your Gmail credentials.
4. Thunderbird will automatically detect IMAP settings and set up the account.

Step 5: Sync Gmail Emails in Thunderbird

1. Once synced, you’ll see the same folders and emails that you uploaded from Outlook.
2. If desired, you can drag and drop the emails to Local Folders in Thunderbird to create a permanent offline copy.

Both the above procedures are efficient to open PST file into Thunderbird email client. You can easily import any desired item into Thunderbird via these solutions.

Are Manual Solutions Effective?

Even though the conventional manual approach is efficient, it has some restrictions. The manual method makes it difficult for some users to precisely export their mailbox items. Some of the major limitations of the manual approach are listed below.

• It is time-consuming and difficult to perform for a novice user. If you are not proficient with MS Outlook and Thunderbird, you may miss some data while exporting.
• This approach does not enable you to choose what items you want to migrate. So, exporting undesired data is another common issue.
• It does not provide flexibility. It means you can smoothly open PST file into Thunderbird but not vice versa or you can not migrate PST to other file types.
• Sometimes, data loss may occur when the procedure is not performed properly.

3rd Method: Import PST to Thunderbird Using Regain Software

Regain PST to MBOX Converter Tool allows you to import PST files to Thunderbird in a few simple steps. This innovative software offers numerous functionalities to ensure data integrity and selective mailbox migration. It offers numerous destination file formats and import PST to Office 365. Above all, this software has a very simple and interactive user interface which makes it a perfect software for novice users.

How to convert PST to MBOX using professional software

• Download and install the Regain PST to Thunderbird Converter tool.
• Run the application and press the Open button to choose the desired file.
• Check the mailbox preview and choose the items you want to export.
• After that, click on the Export button.
• Now, select MBOX in the destination saving option and hit Convert Now.
• Once the PST to MBOX conversion is completed, you can open the MBOX file in the Thunderbird application.

Video Tutorial for Outlook PST to Thunderbird Conversion – Watch Now!

Conclusion

I hope the above article provided all the necessary information on how to open PST file into Thunderbird email client. You can opt for different manual solutions like importing Outlook mailbox to Thunderbird or, you can use Google Takeout. However, if you want precise and accurate migration, we suggest the professional Regain PST to MBOX converter.

Frequently Asked Questions

Q1: Why doesn't Thunderbird support PST files?

Ans: Thunderbird is an open-source email client that uses the MBOX format, while PST files are proprietary to Microsoft Outlook. To bridge this gap, you can convert PST to MBOX using Regain Outlook PST Converter.

Q2: What’s the easiest way to import PST emails into Thunderbird?

Ans: The easiest and most reliable way is to convert the PST file to MBOX using Regain Outlook PST Converter, then import the MBOX into Thunderbird using the ImportExportTools NG add-on.

Q3: Can I import Outlook folders and attachments into Thunderbird?

Ans: Yes. By converting your PST file to MBOX with Regain Outlook PST Converter, you can retain folder structure, email metadata, and attachments when importing into Thunderbird.

Q4: How do I import an MBOX file into Thunderbird after conversion?

Ans: Install the ImportExportTools NG add-on in Thunderbird. Then, right-click a folder, choose “Import MBOX file,” and select the converted file from Regain Outlook PST Converter.

Q5: How can I open PST files in Thunderbird without Outlook?

Ans: The advanced PST to MBOX File converter tool allows you to open PST files into Thunderbird without Outlook installation. Follow the below steps.

• Install and launch the Regain PST to MBOX Converter.
• Click Open and browse the required PST file.
• Check the preview and hit Export.
• Choose MBOX as the saving option and click Convert Now.

Q6: How to open PST files in Gmail?

Ans: Follow the below steps to open PST files in Gmail email account.

• Open the Outlook application in your system.
• Click File >> Info >> Add Account.
• Provide the Gmail email address and set up the account manually.
• Choose the IMAP option and provide the required Gmail password.