Taking the backup of your Yahoo Mailbox on the Mac system in the various file formats like MSG, MBOX, PST, EML, etc. The user can try the Yahoo Backup for Mac tool for downloading the data from Yahoo mailbox to local computer drive simply in few steps. To know more about this tool you can visit here:- https://www.mailvita.com/yahoo-backup-for-mac/
Yahoo Backup Tool is one of the renowned applications suggested by experts to backup Yahoo to PST, EML, EMLX, MSG, MBOX, HTML, and MHTML formats. The application is designed specially so that users can save a backup of Yahoo data locally to their system. There are several formats available to save the backup results by which users can read Yahoo emails on Outlook, Thunderbird, Windows Live Mail, Mac Mail, and others. The standalone utility works alone to backup Yahoo database. One can effortlessly handle the backup process with this program. No deep technical skills are required to backup Yahoo mailbox items. The tool backup emails, email properties (to, cc, bcc, date, from, etc.), 100% accuracy is maintained while export Yahoo emails to Outlook PST and other formats. More info visit here:-https://www.datavare.com/software/yahoo-backup-expert.html
As you want to export Yahoo Mails in PST format, so you can use the Softaken Yahoo Backup Software. This software allows users to download Yahoo Mail sent emails and folders in various options including PST file format. Recently I used this software to export Yahoo mail to PST file format and it works great for me.