Only for ASCII-only, no-attachment, single-folder use.

Here is a breakdown of the methods to convert these files, ranging from free (manual) solutions to professional software.

| Source | MBOX Origin | Pain Point | |--------|-------------|-------------| | Google Takeout (Gmail) | Takeout/Mail/*.mbox | Folder structure lost if you don't use the right tool | | Mozilla Thunderbird | ImapMail/... (no extension) | Each folder is an MBOX file | | Apple Mail (legacy) | ~/Library/Mail/V5/*.mbox | macOS Sierra and earlier | | Old Unix mail servers | /var/mail/username | Single flat file for all incoming mail |

You aren't "converting" so much as parsing MBOX and building a PST from scratch .