If you want to backup of the yahoo mailbox then I would like to suggest you can also try
MailsBackup Yahoo Backup Tool to backup Yahoo email Accounts folder to hard drive, PC or webmail.
Step 1 : Install the Yahoo Archive Tool first, then select Yahoo Mail from the Email Source List.
Step 2: Enter your Yahoo login credentials here and click the "Login" button.
Step 3: Click the backup button after setting the desired saving option and adjusting the filters.
Check for more details at:
https://www.mailsbackup.com/yahoo/
Locked
