The MacProTools MBOX to PST Converter utility is a simple way to convert MBOX files to PST if you're looking to do so. This conversion process won't result in any information loss. Additionally, this program will preserve the data structure—including headers, bodies, and attachments—as it converts your email data to PST. The best tool for everyone is this one. This same program can be used, for instance, to migrate the contents from an MBOX file to another email client or to convert an MBOX file to another file. Getting separate tools for different scenarios is unnecessary.

This one utility can convert MBOX files to a variety of formats.