You can the CloudXena IMAP Email Backup Tool, which is a great option for moving IMAP emails to PST and many different file formats like PDF, MBOX, EML, EMLX, MSG, and OLM, or move them directly to email services like Office 365, Gmail, Yahoo Mail, or any IMAP account. The tool lets you back up many IMAP accounts at the same time and works on Mac. Additionally, this tool provides a free demo version, so you can try before purchasing.