MailStore - MailStore Home - A 100% free single-private-user desktop solution
Vaultastic - Vaultastic’s on-demand SaaS platform provides Protection, Visibility & Control for your Critical Business Data with Agile Cloud Archival.
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
MailArchiva - MailArchiva is an email archiving, email compliance, and e-Discovery enterprise server.
Mail Backup X - Your one stop mail backup and archiving tool for Mac.
MailVault - MailVault is a cloud-based IT software that archives and self-prunes based on user settings.