Change SessionState mode to StateServer/SqlServer

We have a site in ASP.NET, C# and using SiteCore CMS. We were using ASP/NET InProc session and all was working fine. The problem was that the session data was getting lost after sometime. We changed the [login to view URL] and increased the timeout limit, also added sliderexpiration=true in web authentication. The problem is that our session data is big per user and it seems that due to the large session data, the session gets lost fast and is not dependent on the timeout time set in the web.config. Solutions we thought that would solve this problem: 1. Use StateServer / SqlServer 2. Recode the system so only very less data is stored in Session. For now we wish to use 1 (StateServer/SqlServer). We added mode to "StateServer" and got the error "Unable to serialize the session state". Need your help fixing this. If you think that it's better to do 2 if 1 is complicated, you can then re-bid the price for that and we can go that way. Main thing is that we don't want session to loose. ## Deliverables 1) All deliverables will be considered "work made for hire" under U.S. Copyright law. Employer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the employer on the site per the worker's Worker Legal Agreement). 2) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 3) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Employer's environment--Deliverables must be installed by the Worker in ready-to-run condition in the Employer's environment. b) For all others including desktop software or software the employer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this project. ## Platform ASP.NET, C#