The last time I worked on this project everything was fine. That was about 4 days ago. Now, when I open the project, all the references to .Net are not working, I cannot build my project any more. I have tried following the advice in posts here, but to no avail. Even simple things, like Request.cookies - Request is underlined in curlies, and I get 'Request is undefined' when I roll over it. That doesnt seem like I need to just remove and recreate the reference to System.Web.Mvc - which I have tried, and had no luck. Any ideas? Surely there are other issues that can cause this problem... Thank you.