Use Yahoo Backup Tool
is the most secure and trusted software to backup your Yahoo mail in a hard drive. It can save Yahoo emails into different file formats like PST, MBOX, EML, EMLX, MSG, PDF, CSV, GIF, JPG, TIFF, HTML, etc. Moreover, it also offers to migrate mailbox data from Yahoo to Office 365, Gmail, AOL, Hotmail, IMAP, Zoho, Thunderbird, Yandex, iCloud, etc. They enable server space optimization to automatically remove mailbox items upon completing the Yahoo backup process. Additionally, it works smoothly in all versions of the Windows operating system. You can try the trial version of the software to explore the performance.