I regularly use Windows Live Mail to read e-mails and Usenet newsgroup messages. I frequently get unknown errors, which somehow deletes all the downloaded e-mails and Usenet messages from my hard drive, which means I often have to redownload over 80,000 e-mail messages.

Where are these messages stored? How do I make sure that I do not have to redownload all these messages the next time an unknown error occurs.