By chance, I found that having clicked on a folder, if I minimise T'bird to the menu bar and re-open, the correct folder is then displayed. It also seems to freeze sometimes when sending an email: the message 'copying to Sent folder' displays. I do not know whether the e-mail has been sent or not at that point. I am running an oldish Dell Latitude E6410 which I recently 'inherited'. It has Windows 7 Professional The freezing even occurs if the laptop has been idle for some time. Also, the screen is 'totally' frozen, ie I can't minimise from the top right buttons, only by clicking on the T'bird icon in the menu bar at bottom left. I am away now until September 14 and won't be able to respond to any information requests until then. Thanks