title: XmlException Invalid character in the given encoding
body: <p>Hello I searched the internet this exception, 
  I have not found solution so I decided to ask. 
  in a console application I need to search a folder a certain number of xml files. such file is encoded in ANSI. 
    what the application does is to take the file and convert it to utf-8 encoding. 
  but as the cycle goes catch this exception.
  Invalid character in the given encoding. Line 1, position 2757
  I get the xml from a third 
  alguna Idea? muchas gracias.
  this is my code</p>
  
  <p>i get this exception in 3 xmls of 100 </p>
  
  <pre><code>        int Count = 0;
          string sNombre = "";
          string targetPath = @"C:\SomePath\";
          string logError = "log_xml_Error.log";
          if (File.Exists(@"log_xml_Error.log"))
          {
              File.Delete(@"log_xml_Error.log");
          }
  
          Console.WriteLine("press enter");
          Console.ReadLine();
  
          string[] xmls = Directory.GetFiles(targetPath, "*.xml", SearchOption.AllDirectories);
  
          foreach (var sFile in xmls)
          {
              try
              {
                  Count++;
                  XmlDocument xmlDoc = new XmlDocument();
  
                  xmlDoc.Load(sFile);
                  byte[] sXmlByte = Encoding.UTF8.GetBytes(xmlDoc.OuterXml);
  
                  sName = Path.GetFileName(sFile);
                  string sCompletePathXML = @"C:\SomePath\" + sName;
  
  
                  if (!File.Exists(sCompletePathXML))
                  {
                      File.WriteAllText(sCompletePathXML, System.Text.UTF8Encoding.UTF8.GetString(sXmlByte), System.Text.UTF8Encoding.UTF8);
                  }
                  Console.WriteLine(Count);
              }
              catch (Exception ex)
              {
                  using (StreamWriter sw = File.AppendText(logError))
                  {
                      sw.WriteLine(" Error: " + ex.Message + "XML :" + sName);
  
                  }
              }
          }
  
          Console.WriteLine("process complete");
          Console.ReadLine();
  </code></pre>