When I click on "Get Messages" the blue taskbar in the bottom right of the screen goes into motion, and it takes a very long time but eventually quits without anything new being downloaded. If I log in via my Web browser, I can see that there are several e-mails there. It seems that the server thinks the messages have been retrieved (the font is regular, not bold), but Thunderbird is not showing the messages. This is a brand new problem. I've been using TB for years with very little difficulty. The problem happened only after I allowed Thunderbird to update to 38.3. In fact, on my other computer, which was still running 38.2, all the messages are there. I'd like to revert to 38.2 until this problem gets resolved. How? (And how can I prevent the other computer from updating TB? It has already downloaded the update, which happened when I checked its version number. I'm on a W-7 computer here, and the other computer is now on W-10.