Teh Guide

While roundcube doesn't offer the function to export all email, it will usually allow you to connect a desktop mail client via IMAP with that functionality.

I recommend using an open source mail client such as Thunderbird, as it's free and well supported.

1. Download and install Thunderbird
2. Use IMAP to connect to your email
   1. Example settings:
3. Wait for emails to download
4. In the top menu bar, go to Tools > Export to export all emails