ASP.NET Controls Not Recognized

Answer 1

This person who's a tester on the Visual Web Developer Team offered this workaround, which apparently worked:

Close VS, delete schema cache, and re-open VS. You can find the schemas under something like:

C:\Users\Pavel\AppData\Roaming\Microsoft\VisualStudio\10.0\ReflectedSchemas

It is safe to delete all files in this folder.