MailStore - MailStore Home - A 100% free single-private-user desktop solution
PST to Office 365 Wizard - Outlook PST to Office 365 files converter tool supports multiple formats conversion.
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
Conholdate.Total for .NET - Conholdate.Total for .NET is a powerful suite of .NET APIs that gives software developers the ability to create, manipulate, convert, compare & view Word, Excel, PowerPoint, Outlook, Photoshop, AutoCAD, OpenOffice & more than 100 file formats.
Mail Backup X - Your one stop mail backup and archiving tool for Mac.
Gmvault - Backup the emails in your Gmail account.