I was trying to clean up my old email backups and needed a tool that just works.
MacGater MBOX Converter helped me convert MBOX files without losing the original structure, attachments, or email formatting. I used it to
import MBOX to Yahoo Mail after conversion, and everything looked just like it did in my original inbox. It supports multiple export formats like PST, PDF, MSG, DOC, and more. You can even filter your emails by date to skip the junk. Moreover, it is easy to use and runs completely offline on any Mac system.