There are times when you feel almost alone, particularly when you type an error code in google, and nothing comes up.
I got that interesting and particularly verbose exception when doing some XAML refactoring for a Windows Phone 7 application :
An unhandled exception of type 'System.Exception' occurred in System.Windows.dll
Additional information: 0xc00cee65
Turns out it was due to this :
Where two xml namespaces were referencing the same CLR namespaces and assembly. Merging the two namespaces fixed this issue.