Thunderbird has become almost impossible to use, due to Thunderbird frequently freezing and displaying "Not Responding" messages. I'm not sure whether I have unknowingly caused this problem. Each time I start Thunderbird, a scrolling message at the bottom of the window shows emails being downloaded. It seems Thunderbird is downloading all emails (see graphic) from the server when most are already displayed in Thunderbird, and I only need the latest emails. I use imap. I'm unable to stop the emails downloading to verify if that is the cause of my problem or whether the downloads are a normal action. Why are emails being downloaded and how do I stop them? When I delete an email, is it deleted from the Gmail server as I need to reduce space in Gmail. Thanks