My XAML intellisense went away – just like that. The last thing I remember was installing Team Explorer for VS 2008. From that moment on, XAML intellisense disappeared. No Tools->Options settings appear to have any effect. It turns out this may happen after other types of installations related to Visual Studio. If you got this issue, it can probably be corrected with VS 2008 repair, but here’s how to correct it manually (much faster): Open regedit.exe and navigate to: (32 bit system) HKEY_CLASSES_ROOT...