For about two weeks I've been having problems with Thunderbird not downloading messages from Hotmail. Sometimes I will get the blue circle meaning it is not responding and sometimes it will just sit there saying downloading message. It seems to be dropping the link with the server because when I click on another message in the inbox it will reconnect. I've checked the SMTP and IMAP server setting and they seem to be correct. I've also switched anti-virus software and that doesn't not seem to help. I've also tried tweaking the cache settings and the maximum number of server settings to the cache.