If you want to back up your Yahoo mailbox, you can use the MacSonik Yahoo Mail Backup Tool for Mac. This software helps you save your Yahoo emails to different file formats like EML, MSG, PST, MBOX, and more on your computer. It has a date range filter so you can choose emails from a specific time period. The tool has a simple interface, making it easy to use. You can also create a log file of the backup process for future reference.

To Know More: https://www.macsonik.com/yahoo/backup/