The safest way to back up IMAP emails—without losing folders or attachments—is to use a dedicated backup tool that supports IMAP login directly. A tool like Advik Email Backup Wizard works well because it connects to your IMAP server (cPanel, Webmail, Roundcube, Business Mail, etc.) and downloads all your emails exactly as they are.

You just enter your IMAP server details, choose the folders you want (Inbox, Sent, custom folders), and select a format like PST, MBOX, EML, or PDF. The tool preserves attachments, metadata, and your folder structure during the backup. It also includes filters, so you can back up specific emails and avoid duplicates.

This method ensures your entire mailbox—including large attachments—is stored safely on your PC or external drive, ready for recovery or migration whenever you need it.