This is really annoying: a WPF production application that works for months at the customer and hasn't been touched suddenly stopped to compile. I'm getting tons of errors of the type "schema information not found":
Could not find schema information for the element 'http://schemas.microsoft.com/winfx/2006/xaml/presentation:Grid'
Could not find schema information for the element 'http://schemas.microsoft.com/winfx/2006/xaml/presentation:UserControl'.
Could not find schema information for the element 'http://schemas.microsoft.com/winfx/2006/xaml/presentation:Grid.ColumnDefinitions'.
etc...
Anyone out there that has an idea how to fix that?