>>How have you configured sessionState? If you are using cookies, does the failing browser have cookies disabled?
>
>I just found Session State in IIS and it is configured as:
>
>Session State Mode Settings:
>In Process
>
>Cookie Settings:
>Mode: Use Cookies
>Name: ASP.NET_SessionId
>Time-out: 20 mins
>
>use hosting identity for impersonation is checked.
>
>Does this mean I need to ensure cookies are enabled on the workstations' browsers?
As always, it depends. The short answer is yes. Another option is to use a cookie mode of "AutoDetect". I'm not sure what versions of ASP.net support AutoDetect. I know 3.5 does. All the gory details are here
http://msdn.microsoft.com/en-us/library/h6bb9cz9.aspxI feel your pain. So much to learn, so little time!