You can use PST to MBOX Converter software to directly import Outlook file into Thunderbird email client without Outlook using. This software provides batch option to convert multiple PST file to Thunderbird open source profile account with complete emails, formatting, and attachments. There is no need to install MS Outlook application for the migration process. This software comes with dual modes facilities to export single as well as multiple Outlook PST files into Thunderbird email program. It has a very simple user-interface, technical and non-technical users can easily handle and work with this program without any technical skills. During the process, the software keeps all the folder structures without having any changes and data loss. It was workable on both Mac OS and Windows OS including Windows OS including Windows 11. Download the free demo version of the software and convert the first 25 items without any cost.