I posted this before, but the header for my question was corrupted. Anyway, I am referring to Thunderbird 142 Release 64-bit using Windows 10, email provider comcast.net I have a better understanding of what is going on. The GET MESSAGES icon in the upper left now never works, i.e. right clicking it. HOWEVER, if you choose another method for getting messages - I use left click on GET MESSAGES - you still will not get messages, BUT IF YOU CLOSE THUNDERBIRD USING THE "X" ON THE UPPER RIGHT HAND CORNER I.E. DON'T "EXIT" AND THEN RESTART THUNDERBIRD AND THEN USE AN ALTERNATE METHOD TO GET MESSAGES (the right click GET MESSAGES icon still will not work but the left click will), THE MESSAGES ARE LOADED. You can repeat left clicking on GET MESSAGES. But you have to do this every time you start or restart Thunderbird and want to get messages for the first time.