title: App.config decryption fails after a reboot
body: <p>We have a WPF application where we encrypt our connection strings after a first read:</p>
  
  <pre><code>Configuration config = OpenConfiguration(configFileName);
  
  ConfigurationSection configSection = config.GetSection(sectionName);
  
  if (configSection == null)
      return false;
  
  if (!configSection.SectionInformation.IsProtected)
  {
      if (!configSection.SectionInformation.IsLocked)
      {
          configSection.SectionInformation.ProtectSection("DataProtectionConfigurationProvider");
          config.Save();
      }
  }
  </code></pre>
  
  <p>We have this on hundreds of machines, so far everything has worked great. After the first run, the plain text connection strings are encrypted. The decryption should just work automatically. However, we have one machine which is unable to decrypt this information after Windows has rebooted.</p>
  
  <p>My understanding is that the "DataProtectionConfigurationProvider" uses something system specific as its encryption key. 
  Has anyone got any ideas that may help me track down the problem? I am a bit stumped as to why it is this one machine that isn't working. </p>
  
  <p>Thanks in advance</p>