Its wierd, and I cant make head or tail of it. I was writing a webpart today, and I was maintaining a generic stack collection which I wanted to place in the session. What is wierd is that if i were to add object of type Stack <T> to the session, SharePoint says an unrecoverable error has occurred. The moment I changed the stack from a generic to a plain old .NET 1.1 non-generic Stack the error was gone. tags: SharePoint, WebParts, Generics, Session Cross-posted from tariqayad.com...