Update 6/21 - there is a fix for this known issue see KB2468871 look for issue #9 I have found that when you set your app to use .NET Framework Platform Update 1 Visual Studio adds something to your configuration file. It is trying to do the right thing and here is what you get. < configuration...

Humans Go to Control Panel / Programs / Programs and Features / View Installed Updates Use the Search Box to search the updates for KB2495593 KB2478063 Or if you prefer, search the list your self Microsoft .NET Framework 4 Platform Update 1 - Runtime Update Look for .NET Framework 4 Extended Look for...