Encounter this error what trying to compile a Windows Phone 8.1 project: “Xaml Internal Error error WMC9999: Cannot find type System.ComponentModel.TypeDescriptionProvider in module System.dll”
Playing around with my project by try to install Entity Framework from nuget, then remove them later. The compilation start to fail starting from there.
Go to References, look for System.ComponentModel or System.ComponentModel.* references. In my case, it is the System.ComponentModel.DataAnnotations. Remove them and try recompile your project again. It should work now.