Use eSoftTools IMAP Backup & Migration Software to import Proton Mail to Outlook. The interface of this software is fast, secure, and simple, so data loss is not possible. Using this software, you can also perform IMAP to IMAP migration and create a new folder on the IMAP server to save the imported IMAP mails. Users also get a 30-day money-back guarantee if they are not satisfied with the way the software works. So download its free demo now and try it on your system.
Read more- https://www.esofttools.com/blog/add-proton-mail-to-outlook/