I have installed Thunderbird 45.3.0 Thunderbird has been working OK (except sometimes a bit slow!) for some time now. But it is now not displaying any massages when you click on the INBOX or any other folder. Which ever folder you click on it continues the display the pane that is displayed when you click on the email address (the top) folder. That is, the pane containing the account menus - Email - Read messages, Write a new message - Accounts - ... - Advanced Features - ... Just before the problem started the user said that as they started up Thunderbird a message came up saying an COM file was missing. Because of this message I did an uninstall and a fresh install. But unfortunately this has not fixed the problem. OTHER INFO. I have another Windows account on the same computer and Thunderbird works as expected with no issues (appart from the sometimes slow!). We have been using Thunderbird on a number of computers for many years and have never encountered this problem. Has anyone any ideas how this may be fixed?