In the last few days, I've seen a problem where the system tray icon doesn't appear, even though the process is running. The first time it happened, I rebooted, and it reappeared. Today I had to reboot twice before it appeared. Also, when I looked at the preferences, it showed an error that it could not access a logfile because it was in use by another process. I don't know if these error are related, but it's quite a coincidence.