The following program is a great way to backup your personal emails on your Windows computer. If you store large amounts of your email online, it is a good practice to periodically make backups of your emails to your local computer and/or external hard drive to protect your data. Mailstore supports nearly every email format that exists, so whether you are using Thunderbird, Outlook, Gmail, Exchange Server, etc, it should be able to connect and make backups.
Mailstore Download Page:
http://www.mailstore.com/en/mailstore-home.aspx
How to use Mailstore:
http://en.help.mailstore.com/MailStore_Home_Help:Manual
Mailstore Home Page:
http://www.mailstore.com
Users of Microsoft Outlook products can also use Outlook’s built-in export functions:
Outlook 2002 to 2007:
http://support.microsoft.com/kb/287070
Outlook 2010:
https://office.microsoft.com/en-us/outlook-help/export-outlook-items-to-an-outlook-data-file-pst-HA102534110.aspx