For easy and error-free solution to convert MBOX files to PDF format, you can try most reliable ZOOK MBOX to PDF Converter tool. It comes with numerous advanced features so that users can safely and instantly convert MBOX files to PDF format and offers to print them. This utility allows to convert MBOX files of all major emails clients such as Eudora, Mozilla, Thunderbird, Apple Mail, Opera Mail, Entourage, Netscape, Sea Monkey, Poco Mail, etc. 

For more info- https://www.zooksoftware.com/mbox-to-pdf/