When you click on send/recieve some of your emails may download, but the rest fail to download.... or it might be that when you try to download ALL of your emails, some of them don't actually download.

This can be a problem with the server, and if you host your emails with us you can open a support ticket to ask us to look into this for you - specifying the email address that you're having a problem with.

However you should first review the following article from Microsoft as in 9 out of 10 cases it will resolve the problem:

http://support.microsoft.com/kb/813514/en-us