Click on the Add File button on the welcome screen.If you wish to convert files on a MAC platform, use this tool instead:
Install SysTools MBOX Converter on your system.
Professional Solution (Using SysTools MBOX to PDF Converter ) to export MBOX to PDF file To overcome such situations, and to ensure that attachments are maintained along with emails in PDF files, one must opt for professional method. There are no options to customize your PDF documents.Requires technical expertise and granular knowledge.Attachments are discarded during the process.Choose the folder where the PDF files will be saved and click Select Folder.Right-click and select Save Selected Messages > PDF format.Now, select the emails that you want to convert to PDF.Import the MBOX file in the MBOX email client by right-clicking on Local Folder and choosing ImportExportTools NG > Import mbox file.Click Install Now and restart Thunderbird once its done.Look for ImportExportTools NG and click Add to Thunderbird.In the Add-ons Manager window, search for “ ImportExportTools”.Start the MBOX email client and hit Tools > Add-ons (Press Alt key if menu is unavailable).(Note: Before following the method, make sure that Thunderbird is installed.) Manual Method to Convert MBOX to PDF File Format Professional Method: The professional method provides a proficient way to generate PDF files while maintaining attachments.