there are several columns across the top such as "Subject" "from" "Date" etc. The one that displays the summary of the message (i'm sorry I don't know what it's called because its no longet there) has disappeared. So I now have to open each email to read. I have tried resetting to default column settings. I have tried turning "on" the various columns without any luck. One of the columns is "thread" . I'm assuming that is the one I need. But I am not sure. When i turn that "on" it appears as a very narrow column which is unable to be read. Although I have tried to widen this column by hovering and dragging when the double sided arrow appears, it will not widen. ie: I grab the edge of that column and try to drag it across the page but it won't move. Is this the column I need to read the summary of new emails? Or should I be looking for something else? Please note that thunderbird has been installed and working and displaying messages for several years. The message summaries just disappeared from the screen about 48 hours ago. I don't think I have done anything to alter settings and options as I have had no need to so.