How to Import PST File to Thunderbird in 2026?

rohit1208

If you're switching from Outlook to Thunderbird, you might wonder how to import PST files. Unfortunately, Thunderbird does not support direct PST import, especially in the latest versions.

But don’t worry—there are simple workarounds you can follow.

Why Direct Import Doesn’t Work?

PST is a proprietary Outlook format, while Thunderbird supports MBOX format. That’s why you need an intermediate step.

Method 1: Using Outlook (Limited & Outdated)

This method works only in older Thunderbird versions:

1. Set Outlook as the default email client
2. Open Thunderbird
3. Go to Tools → Import → Mail
4. Select Outlook and import data

Limitation:

• Works only with older Thunderbird versions
• Requires Outlook installation
• Imports emails only (not full data)

Method 2: Convert PST to MBOX (Recommended in 2026)

This is the most reliable and widely used method.

Steps:

1. Convert PST file into MBOX format
2. Open Thunderbird
3. Import the MBOX file using ImportExportTools NG add-on

Why this works:

• Thunderbird fully supports MBOX files
• Ensures better data accuracy and structure

Suggested Solution: Cigati PST Converter

For a smooth and accurate migration, you can use Cigati PST Converter.

Key Benefits:

• Converts PST to MBOX format easily
• Supports bulk PST file conversion
• Maintains folder hierarchy and attachments
• No need to install Outlook
• User-friendly interface for beginners

In 2026, the best way to import PST into Thunderbird is by converting PST to MBOX using a reliable tool. Manual methods are outdated and limited, while professional tools ensure fast and secure migration.

martin23t

The manual method involves first importing the PST file into Microsoft Outlook and then using the built-in “Import” option in Mozilla Thunderbird to import mail from Outlook. While this approach is straightforward on the same Windows system, it only works when Outlook is properly configured and detected by Thunderbird. Additionally, it often fails on new setups or different operating systems and may not import all data accurately, especially with large or multiple PST files.

On the other hand, the Advik PST Converter can import PST to Thunderbird quickly. With this utility, you can transfer multiple PST files at once. The software ensures complete data transfer, including emails, attachments, and folder hierarchy, without any data loss. With its user-friendly interface and fast processing speed, even non-technical users can easily import PST files to Thunderbird without the need for Outlook or complicated steps.

1. Launch the software and add .pst file into software.

2. Select the mailbox folders you want to import.

3. Choose Thunderbird as a saving option.

4. Click on the Convert button to start the importing process.

reginhardbohm

To import a PST file into Thunderbird in 2026, it's usually easiest to first convert the PST file to MBOX format, because Thunderbird works well with MBOX files. The PST file import may be difficult especially when the file contains several folders or even attachments/old emails.

This could be made easy by using FixVare PST to MBOX Converter software. The converter is compatible with Windows, and it converts the emails stored in PST files of Outlook to the MBOX format. The process does not tamper with any folders, attachments, and email information. Then, the MBOX file could be imported to Thunderbird.

The free demo is helpful for checking the result before buying. It also works offline, so mailbox data stays on the system instead of being uploaded online.