Hello,
I recently updated my Silverlight project from 2011 Q2 to 2011 Q2 SP1. Everything works great in VS 2010, but when I bring up any of my XAML files in Blend 4 I get the attached error message. Let me know what additional details I can provide. I've tried Cleaning and Rebuilding the project, but that didn't help. I downgraded back to 2011 Q2 and everything works fine.

Thanks!

Hi Mike,

 

We are not aware of such an issue related to the Blend support for RadControls/Silverlight.
Since you have added the full list ot references related to any RadControl you should not get such an error.  May you please share with us a bit more details about the problem you have experienced in Expression Blend and which RadControls you are currently using? Furthermore you may also submit a new support ticket and attach a runnable project where we can see what might be wrong. 

Best wishes,
Vanya Pavlova
the Telerik team