I have an asp.net 3.5 appllication that is using three controls. One for the header, one for the menu, and the last is for footer. In the header I am grabbing the users nt id from the html header and filling a session variable. For some of my users this is not having any problems. For others the page just is stuck trying to load. No error gets thrown. In the IIS log I see warnings and expanding them I see the user string is blank. What would be causing these users to not be passing their nt id in the header?