The list of all messages in all accounts has gone blank on one machine. I can click a line, or right click, for example, and delete a message (a blank line), and on another machine with working T-Bird it shows that the message corresponding to that line is deleted. So the messages are there, It's just that the lines are all blank, so the aggregate inbox looks empty. The Inboxes for the indivual Email accounts properly display a message list. I've tried repairing each inbox, and compacting each. I closed T-Bird and deleted the foldertree.json, and session,json files then started T-Bird. But none of that helped. What now?