If you are looking for the best way to convert PST files to MBOX format then, I would like to suggest you, use a tool PST to MBOX Converter to convert Outlook PST files. It can easily migrate emails of Outlook PST file MBOX with all their attachments. You can also apply its date range filter to select specific emails as per date. It can export data from password-protected PST files. It has a simple and interactive graphical user interface that makes the tool easy to use. This utility smoothly works on all version of Windows and make the operating system.