I have a problem with Thunderbird (TB) installed on a Windows 10 PC. I think the problem may started with release 102.5.1, but I cannot be sure. I removed and reinstalled TB but the problem continues and is as follows. I seem to be able to run TB only in Troubleshooting Mode. If I close TB and wish to reopen it by clicking on the TB icon on the task bar, all I get is an expanded task bar item comprising the icon, the number of unread emails and the name of the TB folder that was last in use. The same happens if I search for the TB app and open it from there. I found that if I right click the TB icon in the task bar, a contextual menu appears. Selecting the TB option has the same effect as above, but selecting the “Write new message” option opens a new window with (what I believe to be) the normal screen layout for composing a new email message which I can then send as usual. If, instead of composing a new message, I navigate to the Help menu and select “Troubleshoot mode” and accept the options to “Restart” and then “Continue in Troubleshoot mode”, I find that I can use TB petty much as normal with all my folders and emails available. If at anytime I choose to go to Help and Turn off troubleshoot mode, the original problem recurs. Likewise, the original problem recurs if I close and restart TB. How can I get TB to open immediately into the normal mode? BTW, I do not use the calendar, but email addresses are suggested so presumably some form of address book is in use.