Unity Crash on Adding to List Array, bug?

Hey guys, I am creating a custom editor and I have a list array of custom class. What I want to do is empty that array and dump a new array into the original one.

What I am doing:

 //serialize original list array
 IFormatter formatter = new BinaryFormatter();
 Stream stream = new FileStream("Assets/Resources/LevelGFX_" + currentLevelID.ToString() + ".bin", FileMode.Create, FileAccess.Write, FileShare.ReadWrite);
 formatter.Serialize(stream, test.Stages);
 stream.Close();
 
 //retrieve previously serialized list array and insert into obj variable
 IFormatter formatter = new BinaryFormatter();
 Stream stream = new FileStream("Assets/Resources/LevelGFX_" + currentLevelID.ToString() + ".bin", FileMode.Open, FileAccess.Read, FileShare.Read);
 List<CStage> obj = (List<CStage>) formatter.Deserialize(stream);
 stream.Close();
 
 //clear original array and insert obj array into orignal array
 foreach(CStage s in test.Stages.ToArray())
 {
    test.Stages.Remove(s);
 }
 foreach(CStage s in obj)
 {
    test.Stages.Add(s);    
 }

Here is the CStage Class:

 using UnityEngine;
 using System.Collections;
 using System;
 
 [Serializable]
 public class CStage {
     
     public string StageName = "New Stage";
     public float StartTime = 0F;
     public float EndTime = 150F;
     public float SpeedMin = 1F;
     public float SpeedMax = 2F;
     public float MinSize = 2F;
     public float MaxSize = 4F;
     public float speed = 1F;
     public float ZDepth = 5F;
     public float Frequency = 2F;
     public bool Sequential = false;
     public float SequentialFudge = 2F;
     public float RotationY = 0F;
     
     
     [NonSerialized()] public GameObject EntryModel;
     [NonSerialized()] public GameObject[] InbetweenModels = new GameObject[5];
     [NonSerialized()] public GameObject ExitModel;
     
     public bool FlipRandomally = false;
     public bool RandomizeRotation = false;
     [NonSerialized()] public Color TintMin = Color.white;
     [NonSerialized()] public Color TintMax = Color.red;
     
     //pos
     [NonSerialized()] public Vector2 XminMax = new Vector2(-5F, 7F);
     [NonSerialized()] public Vector2 YminMax = new Vector2(-4F, 4F);
     [NonSerialized()] public Vector2 ZminMax = new Vector2(0F, 8F);
     
     //internal
     public bool selected = false;
     public int gridY = 0;
     public int buttonWidth = 100;
     public int buttonHeight = 60;
     public bool modelsFoldout = false;
     public bool additionalFoldout = false;
     public bool stopped = false;
     public float rendererx = 5F;
     
     //test
     public GUIStyle gstyle = new GUIStyle();
     public bool colorSet = false;
     
     //state
     public enum stateM
     {Middle, Entry, End}
     public stateM state = stateM.Entry;
 
 }
 

However this causes Unity to crash. Any ideas will be greatly appreciated!