Helping out an old friend and former co-worker, we ran into an issue where he was unable to save anything in session state between requests in ASP.NET.
Well, we eventually figured out the issue - his server had an underscore in the name....
PRB: Session Variables Do Not Persist Between Requests After You Install Internet Explorer Security Patch MS01-055After you install security patch MS01-055 for Microsoft Internet Explorer 5.5 or 6.0, you may encounter the following problems:
Note These problems can also occur after you install a more recent patch that includes the fix that is provided in security patch MS01-055.
Because ASP session state and session variables rely on cookies to function, ASP cannot maintain session state between requests if cookies cannot be set on the client.
This issue can also be caused by an incorrect name syntax in a host header.
For now, he is going to use cookieless=true session state to get around this issue until the servername can be changed.