title: Only one configSections element allowed per config file and if present must be the first child of the root configuration element
body: <p>I am developing the console application and when I run the .exe file, I get the following error:</p>
  
  <blockquote>
    <p><code>system.Configuration.ConfigurationErrorsException</code>:  Only one <code>&lt;configSections&gt;</code> element allowed per config file and if present must be the first child of the root <code>&lt;configuration&gt;</code> element.</p>
  </blockquote>
  
  <p>Here's my <code>App.config</code> file:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;configuration&gt;
      &lt;startup useLegacyV2RuntimeActivationPolicy="true"&gt;
          &lt;supportedRuntime version="v4.0"/&gt;
      &lt;/startup&gt;
      &lt;configSections&gt;
          &lt;section name="Reva.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" /&gt;
          &lt;section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" /&gt;
      &lt;/configSections&gt;
      &lt;!-- ... --&gt;
  </code></pre>
  
  <p>However, if I remove the following <code>startup</code> section, then it works fine</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;startup useLegacyV2RuntimeActivationPolicy="true"&gt;
      &lt;supportedRuntime version="v4.0"/&gt;
  &lt;/startup&gt;
  </code></pre>