'Microsoft.VisualStudio.Editor.Implementation.EditorPackage' package did not load correctly
Visual Studio 2012 Ultimate
Removing "C:\Users\UserName\AppData\Local\Microsoft\VisualStudio\11.0\ComponentModelCache" solved the problem
Visual Studio 2012 Ultimate
Removing "C:\Users\UserName\AppData\Local\Microsoft\VisualStudio\11.0\ComponentModelCache" solved the problem