First, ty for the rep and kind words. As to why it does not work, I cannot answer. Your email client is corrupted. When downloaded some corruption set in, which prohibts use in the normal manner. If it were a more serious problem which did not have an alternative solution, we could probably fix it. I could tell you to uninstall, save your emails and then install, again and that would probably work. I have given you the method that you could use to fix the problem, but I would not try. In fact, I normally use the method that I suggested that you use. In any event, I hope that you enjoy your OS, and all your mail brings good news.
Richard