The new backup in Thunderbird seems a great idea for large organisations but for domestic users trying to copy and save a CSV file of their little address books, it's a disaster. Please reintroduce the "Export Address Book" button. I note on your forums there are many requests for sorting address books since the introduction of the new system I have 4 computers in my home and all I want to do is have the same or similar address book on each one. Otherwise, it's great.