app.config "Could not find schema information" after converting to Visual Studio 2010 / .Net 4.0

After upgrading my project to Visual Studio 2010 and .Net 4.0, my app.config开发者_Go百科 file generates these messages upon building the project:

• Could not find schema information for the element 'supportedRuntime'.
• Could not find schema information for the attribute 'version'.
• Could not find schema information for the attribute 'sku'.

Here is my entire app.config file:

<?xml version="1.0"?>
<configuration>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0,Profile=Client"/>
  </startup>
</configuration>

If I create a new VS2010 project and literally copy/paste the same app.config file, I receive no such messages.

Obviously these messages are not causing any runtime problems, but they are still annoying and disconcerting.

How do I fix whatever problem is making these messages appear?

I see the answer at app.config configSections custom settings can not find schema information, but I see nowhere in the properties list to enter the path to the schema.

Thanks.

I changed the schema from DotNetConfig to DotNetConfig35 and it took care of the issue. This is available in the properties of the app.config file.

Right clicking the app.config file in solution explorer gives the properties of the file, right clicking in the edit window of the app.config file itself gives the properties of the XML document.

Are you sure the conversion went ok? Maybe the correct target framework wasn't configured. Open your project properties and check if the target framework is actually .NET Framework 4 or .NET Framework 4 Client Profile.

Remove the following section in app.config:

<startup> 
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0,Profile=Client"/> 
</startup>

Try to kill the process in Task Manager next time, if it's already running.

P.S: It might be running at a remote machine.

Update: Since there is no solution I repeat my advice... Stop down voting. Maybe it's a bug but it might be related to un-terminated debug process. Just examine the Task Manager and kill xyz.vhost.exe of fx2.0, if any.