I have a scenario where occasionally people will try to hit non-existent web pages in my virtual directories ( they're trying to hit pages that used to exist in a previous system ). I am trapping for the generated error in the Global.asax Exception event and am trying to direct them to an information page. This is a generic page I use for showing messages. Message data is loaded into an object which is stored in Session and retrieved by the generic show message page. Generally works well.

In this case, however, when I try to load the message object into Session it throws an exception complaining that the Session is null, so there's no Session to load the object into. I.e. for some reason when the HTTP 404 error is thrown it seems to destroy the Session.

Has anyone seen this, what causes it and what can be done about it?

Thanks,
Bill