Format a document XML for readability.

IndentXml.cs

using System.IO;
using System.Text;
using System.Xml;

class IndentXml
{
	public static void Main()
	{
		var xmlDocument = new XmlDocument();
		xmlDocument.Load(@"C:\Original.xml");

		// NOTE: This causes XML to have an attribute of UTF-16 encoding. You may need to change this manually.
		var xmlContents = xmlDocument.Indent();
		File.WriteAllText(@"C:\Formatted.xml", xmlContents);
	}
}

static class XmlDocumentExtension
{
	public static string Indent(this XmlDocument xml)
	{
		var xmlWriterSettings = new XmlWriterSettings
		{
			Indent = true,
			IndentChars = "\t",
			NewLineChars = "\r\n",
			NewLineHandling = NewLineHandling.Replace
		};

		var stringBuilder = new StringBuilder();

		using (var xmlWriter = XmlWriter.Create(stringBuilder, xmlWriterSettings))
			xml.Save(xmlWriter);

		return stringBuilder.ToString();
	}
}