Guide for SysTools MBOX Converter
After adding MBOX file click on Export button, then you will get Export window in which you can do the settings: like: select folder to export, change saving location & exporting format and then click Export to start the conversion process. And you will get notification message after successful conversion.
As the email load in the Preview window, you can stop the process in between by clicking Stop button.
Next, you can switch the view mode of the emails, i.e. either as Horizontal or Vertical View as per your convenience.
As the export process begins, you will get the following window, showing the details as displayed in the image below.