What is generally recognised as the best way to handle a welcome message for a user whose username may not be known? In my menu I have a "Welcome " title, with the user's photo but thinking defensively I need some default text in case their user name is not in the system or some error happens and it is an empty string. I cannot have simply "Welcome " as the spaces will look odd. Same for centering the text (but that may be the best option).
Is there some alternative text I could use? "Welcome User" seems too impersonal and will break the user's experience I feel.