Hello!

I just recently activated my ms outlook and every time I open it, it automatically imports e-mails from my yahoo account (mail.yahoo.com), deleting all the e-mails from the yahoo server.
Can anyone please tell me how to stop this, and how can I restore my e-mails on the yahoo account?? I would prefer if outlook could work together with yahoo and no e-mail gets deleted. It`s really important!

Thanks!