You can’t import a PST file directly into Thunderbird because Thunderbird does not support Outlook PST format. But don’t worry—there is a simple and safe way to do it.
The easiest method is to first convert the PST file into MBOX format, which Thunderbird supports.
Use a reliable PST converter tool (for example, a PST to MBOX converter).
Convert your Outlook PST emails into MBOX files.
Open Thunderbird on your computer.
Use the ImportExportTools NG add-on in Thunderbird.
Import the converted MBOX files into Thunderbird folders.
This method keeps your emails, attachments, and folder structure intact.
Manual options are limited, time-consuming, and often cause missing emails or formatting issues. Using a dedicated conversion tool reduces errors and saves time.
If you have a large PST file or multiple mailboxes, a professional conversion tool is the safest option to
import PST to Thunderbird without data loss.