Thunderbird MBOX files can be converted to PST format using a variety of third-party tools available on the online internet market. However, when it comes to reliable and safe tools, eSoftTools Thunderbird to Outlook Converteris the most suitable option. It can also offer a live preview facility, which allows you to check all of the data. It supports all windows and Outlook. You can also free export Thunderbird emails to PST files by using its free demo pack in which you can convert the initial 25 items from each Thunderbird folder.