I disabled vipre on the 8.1 computer and it didn't solve tb problem; I disabled add-ons and that wasn't it either. tb freezes when I delete items and I have to use task manager to shut it down. I am running same version of vipre antivirus on other computer with windows 7 and tb works fine there. I read all the posts and it seems to me you do have a problem integrating with 8.1. I am using pop server, not imap. And this problem with tb is quite time consuming and frustrating.