I'm not sure why, but lately Visual Studio cannot seem to find the schema used in XAML on the root Window.

This is the error message I'm getting: 

> 
> Message 1 Could not find schema information for the element 'http://schemas.microsoft.com/winfx/2006/xaml/presentation:Window'.
> 
> 
> 

The error results in IntelliSense not working. However, the project still compiles and runs as expected. The problem is the same in every project I open. Starting on a new project gives me the following XAML: 

```
<Window x:Class="WpfApplication2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>

    </Grid>
</Window>

```

But I'm getting the same error.

I've tried, without luck, all of the following:

* Reinstalling Visual Studio 2010
* Reinstalling .NET
* Removing the Visual Studio directory (\Users\[User]\Documents\Visual Studio 2010).

What do I do to fix it?