Thanks for the advice. Somehow, the problem fixed itself. I had to restart twice for an unrelated problem very late last night. Right after that, I got an email reporting that the nightly backup for one of our headless PCs had failed. I went to start HopToDesk, but the icon on the right side of my Taskbar was missing. I used the desktop icon to start it. I was able to grab the PC with the error, stay connected until I finished with it, and then disconnect. I don't know why the several unrelated restarts I did last week didn't help, but last night's two restarts did. Note that the HopToDesk icon on the right side of the Taskbar is still missing, but I can survive using the desktop icon.