If you created Metro style (WinRT) projects in Visual Studio “11” developer preview (alpha) and you try to open them up in the beta you will have a few load issues. These are ones I have found in my apps so it is not exhaustive, but seems like the most common.
Projects will not load
The projects themselves will not load with the following error: The imported project "C:\Program Files (x86)\MSBuild\Microsoft\WindowsXaml\v1.0\Microsoft.Windows.UI.Xaml.CSharp.targets" was not found. Confirm that the path in the <Import> declaration is correct, and that the file exists on disk.
The solution to this is to open the project file and navigate to the <Import> node and change the path from v1.0 to v11.0 (see the highlighted extra 1 in the image below that is needed):
Compiler Directive
If you used the compiler directive WINRT that has been changed to NETFX_CORE so you will need to update your code.
Package fails to build
The package fails to build/deploy and complains about an InitialRotationPreference attribute. To solve this open the Package.appxmanifest file and find the <VisualElements> node and you should find an line similar to this:
<VisualElements DisplayName="AtomicMVVM Metro Style App Demo" Logo="Images\Logo.png" SmallLogo="Images\SmallLogo.png" Description="AtomicMVVM Metro Style App Demo" ForegroundText="light" BackgroundColor="#000000" InitialRotationPreference="portrait">
What you need to do is remove the InitialRotationPreference attribute from the end, so it ends like this:
<VisualElements DisplayName="AtomicMVVM Metro Style App Demo" Logo="Images\Logo.png" SmallLogo="Images\SmallLogo.png" Description="AtomicMVVM Metro Style App Demo" ForegroundText="light" BackgroundColor="#000000">
Big load failure image from: http://www.hostedfile.com/pictures/76451/big-load-failure.html