How do I convert a pst file to a mbox file for Windows? To convert pst to mbox, use the eSoftTools PST to MBOX Software. Email properties are maintained during the pst to mbox conversion. It has a number of features, including:- It shows a live preview of the pst to mbox conversion. You'll also find a date filter option here. All users have access to the demo version. You can convert 25 emails per folder in the demo version.