When you use C++ Store projects, the projects do not have IntelliSense immediately after you upgrade to Microsoft Visual Studio 2013 Preview.
This problem occurs because of an issue in the project reference resolution.
To work around this problem, use one of the following methods:
Change the Platform Toolset properties to v110. To do this, right-click the project, click Properties, click Configuration Properties/General, and then click Apply. Then, change back to v120 by following these same instructions.
Close the solution, delete the .sdf file from the solution folder, and then reopen the solution.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Visual Studio 2013 Preview, Visual Studio Express 2013 Preview for Desktop, Visual Studio Express 2013 Preview for Web, Visual Studio Express 2013 Preview for Windows, Visual Studio Premium 2013 Preview, Visual Studio Professional 2013 Preview, Visual Studio Test Professional 2013 Preview, Visual Studio Ultimate 2013 Preview