Hi All, We had Thunderbird installed on our Windows based computer and it worked fine. When changed to an iMac and installed Thunderbird then every time the computer shuts down or loses power Thunderbird disappears and has to be re-installed. Also all of our emails that were previously in the Inbox have gone. Once re-installed it works normally except that there are no emails in the Inbox other than those time stamped since the last shutdown. What have I done wrong?