When I enable solution wide inspection (and sometimes even when I do not) ReSharper returns errors for just about every single one of my View files in my ASP.NET MVC application, saying that the core ViewPage objects Html, Model, Request, and some others are unknown symbols. If I go to the file and select any part of the unknown symbol and simply retype it the error goes away, but it never stays away. I really like being able to use solution-wide inspection to keep an eye on things, but when it contains 74 errors that are false positives then it's pretty much useless. :\
I am currently using the 5.0 EAP client of resharper, but I was also experiencing this issue in 4.5.