Whenever I try to create a new VSPackage project in Visual Studio 2013 Update 5, selecting C# as the language, I get an error when it tries to open the resulting solution, saying, "The element <#text> beneath element <Project> is unrecognized.<path to the csproj file>".
If I try to create a new VSPackage project selecting C++ as the language, I get an error saying, 'Unable to read the project file "VSPackage2.vcxproj", <path to vcxproj file>(183,3): The element <#text> beneath element <ItemGroup> is unrecognized.'
I've just uninstalled and reinstalled Visual Studio 2013, Updates 1, 2, 3, 4 and 5, the Visual Studio 2013 SDK and the Visual Studio 2013 Visualisation and Modelling SDK, making no difference whatsoever.
When I look at the csproj file (and the generated cs files), there are lots of "%EditorStart%" and "%EditorEnd%" scattered through them, which seem pretty evidently places where something's supposed to be substituted into the file.
What causes this problem? Is there a fix or a workaround?