I am in the process of upgrading to MVC4. I have followed the instructions at http://www.asp.net/whitepapers/mvc4-release-notes#_Toc303253806 but in my Razor views and layou
Just to expand on Matt DeKrey's answer, just deleting the csproj.user file (without needing to recreate solutions) was able to fix the problem for me.
The only side effect I had was I needed to reset the Start Action back to using a specific page.