You can convert many PST files to MBOX format with TrustVare PST to MBOX Converter Software, and you won't lose any data. It can convert PST files from any version of Outlook to another format and then upload them to any MBOX-based email client, such as Eudora, Mozilla, Thunderbird, Entourage, Opera Mail, and more. Without any extra work, this is the best way to add Outlook data files to MBOX.
