If you are looking for a reliable tool to backup your Yahoo data then, use the MacSonik Yahoo backup tool. This utility helps to backup entire Yahoo mailbox items like contacts, emails, calendars, etc with zero data alteration. You can save the Yahoo mails in PDF, PST, MBOX, and other various file formats. Additionally, it also helps to import Yahoo mail to Gmail, Thunderbird, Office 365, etc. The Yahoo backup tool for Mac maintains data security and originality throughout the conversion and removes identical emails during the process. It also free up the server space after creating a backup of Yahoo emails securely.