I recently applied the latest update and now I can see all the message headers up to the update, but no new ones. The headers displayed do not have any messages attached. I have confirmed that the problem is on this computer only as my laptop which does not as yet have the latest update applied, works as normal in terms of new messages and old messages are also there. This problem only seems confined to my inbox. I have tried re-downloading my messages, checked all the settings and so forth and that works but still message bodies in the inbox. I have checked my password. I have used Thunderbird pretty much since it started (also Firebox has been my primary browser for many years and still is.

The other thing I did around this time was to install the Thunderbird app on my Android phone. As part of this I generated a QR code to copy settings etc over to the phone. 

I can see that I have my 2 account headers on the phone, but nothing else.