The software quickly import email messages from various formats of MBOX files into Outlook for free. It can handle mboxo, mboxrd, mboxcl, mboxcl2, and others, making email transfer easy.

One of the standout features of this tool is its ability to store the original Internet headers in your Outlook messages when importing from MBOX files. Additionally, it can automatically move successfully imported MBOX files to another folder so you don't end up with duplicate messages.
But perhaps most importantly, this utility is very versatile. It can be used via command line in a variety of scripts and scenarios, making it a great choice if you need to automate the migration of MBOX files for multiple users. Overall, if you're in need of a tool to import MBOX files into Outlook, give this one a try.
Version 4.20: New features and enhancements.