The best solution to export IMAP email folders to MBOX files is eSoftTools IMAP Backup & Migration software. It also lets you export emails from single and multiple mail folders of an IMAP account. Its interface is straightforward and simple which makes it easy to use for all users. Also, it provides you error-free backup. This software works on all versions of Windows like 7, 8, 10 and the latest versions as well.
Read more- Export IMAP email folders to MBOX files