To Backup IMAP mailboxes to PST format? Then I would like to suggest you can also try Mailsbackup IMAP Backup Tool to backup IMAP mailbox emails to local PC as PST, MBOX, EML, PDF, etc. IMAP Backup and Restore tool enables to backup IMAP Server and IMAP account to IMAP, Gmail, Office 365, etc. You can also save IMAP account emails to various desktop based email clients such as Thunderbird, Outlook, Lotus Notes, Windows Live Mail, Zimbra, etc. 

Check for more details at: https://www.mailsbackup.com/imap/

If you want to backup IMAP mailboxes to PST, check out the Shoviv IMAP Backup Tool for a reliable and efficient solution. This software allows users to export IMAP emails into PST format while preserving folder hierarchy, email properties, and attachments. It supports all major IMAP servers, including Gmail, Yahoo, Zoho, and Office 365. Advanced filters help back up selected folders, date ranges, or specific emails, saving time and storage space. The tool also avoids duplicate emails during backup and supports incremental backup. With its easy-to-use interface and free demo version, Shoviv IMAP Backup Tool ensures secure and accurate IMAP mailbox backup.