New to XML in C#, can't get anything to work.

Currently the error I keep running into is :

InvalidOperationException: To be XML serializable, types which inherit from IEnumerable must have an implementation of Add(System.Object) at all levels of their inheritance hierarchy. UnityEngine.Transform does not implement Add(System.Object).

So what I'm trying to achieve is, I have a main list of SoundElement and every SoundElement has a ByteInfo object within them. I want to go through the list of SoundElement's and save out the ByteInfo Data of each one..

I have removed stuff that shouldn't be relevant form the code to make this post shorter.

SoundElement

 using System.Xml;
 using System.Xml.Serialization;
 
 
 public class SoundElement : MonoBehaviour 
 {
     [XmlAttribute]
     public ByteInfo _byteInfo;
 }

ByteInfo

 [XmlType("ByteInfo")]
 public class ByteInfo : MonoBehaviour
 {
 
     //trackInfo
     [XmlElement("byteLength")]
     public float byteLength;
     
     [XmlElement("byteDirectory")]
     public string byteDirectory;
     
     [XmlElement("byteName")]
     public string byteName;
 
     [XmlElement("byteFav")]
     public bool byteFav;
 }

SoundList

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine.UI;
 using System.Xml;
 using System.Xml.Serialization;
 using System.Linq;
 using System.IO;
 
 
 [XmlRoot("ByteList")]
 public class SoundListNew : MonoBehaviour 
 {
     [XmlArray("Bytes")]
     [XmlArrayItem("Byte")]
     public List<ByteInfo> clipArray;
 }

This has left me with a headache and sorting this out as soon as possible would be really really nice. Any help appreciated.