I have used TB for several years. Recently I have experienced the problem of all new emails disappearing immediately after being downloaded. The inbox shows a number of new new emails. When I click on the inbox all the emails are gone and the number also is gone. I have several subfolders where I stored emails. They are also empty. I downloaded a new copy of TB but got the same results. I can go to the server (Comcast) and see the emails before they are downloaded. How can I regain the ability to successfully download and retain emails in TB?