title: Changed Target .NET Framework in Visual Studio creates errors
body: <p>I was originally writing my program for .NET 4.0... however, recently I changed the target framework for .NET 3.5... the program still works fine, but now I'm running into a rather odd error. In the past, when I built the program, it would generate the .exe and that is it. Now it generates a .exe and a .exe.config.</p>
  
  <p>Should still be fine right? Nope, in the .exe.config file, it has the following code:</p>
  
  <pre><code>&lt;configSections&gt;
      &lt;sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"&gt;
          ...
      &lt;/sectionGroup&gt;
  &lt;/configSections&gt;
  </code></pre>
  
  <p>As you can see, it says <code>Version=4.0.0.0</code> and because of this, when I run the program I get an unhandled exception assembly error. Its pretty easy to fix, I just delete the .exe.config file and all is well. But its starting to become a pain, to do this on each and every build.</p>
  
  <p>What can I do to fix this?</p>