diff --git a/External/KdTree/KdTreeLib/KdTree.cs b/External/KdTree/KdTreeLib/KdTree.cs
index 96cf75ea6..59e665bcc 100644
--- a/External/KdTree/KdTreeLib/KdTree.cs
+++ b/External/KdTree/KdTreeLib/KdTree.cs
@@ -3,8 +3,9 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Runtime.Serialization.Formatters.Binary;
+using System.Runtime.Serialization;
 using System.Text;
+using System.Xml;
 
 namespace UnityEngine.ProBuilder.KdTree
 {
@@ -25,6 +26,7 @@ public DuplicateNodeError()
 	}
 
 	[Serializable]
+	[DataContract]
 	class KdTree<TKey, TValue> : IKdTree<TKey, TValue>
 	{
 		public KdTree(int dimensions, ITypeMath<TKey> typeMath)
@@ -40,12 +42,16 @@ public KdTree(int dimensions, ITypeMath<TKey> typeMath, AddDuplicateBehavior add
 			AddDuplicateBehavior = addDuplicateBehavior;
 		}
 
+		[DataMember]
 		private int dimensions;
 
+		[DataMember]
 		private ITypeMath<TKey> typeMath = null;
 
+		[DataMember]
 		private KdTreeNode<TKey, TValue> root = null;
 
+		[DataMember]
 		public AddDuplicateBehavior AddDuplicateBehavior { get; private set; }
 
 		public bool Add(TKey[] point, TValue value)
@@ -370,7 +376,8 @@ public KdTreeNode<TKey, TValue>[] RadialSearch(TKey[] center, TKey radius, int c
 			return neighbourArray;
 		}
 
-		public int Count { get; private set; }
+		[DataMember]
+	public int Count { get; private set; }
 
 		public bool TryFindValueAt(TKey[] point, out TValue value)
 		{
@@ -578,20 +585,22 @@ public void Clear()
 
 		public void SaveToFile(string filename)
 		{
-			BinaryFormatter formatter = new BinaryFormatter();
+			var serializer = new DataContractSerializer(typeof(KdTree<TKey, TValue>));
 			using (FileStream stream = File.Create(filename))
+			using (var writer = XmlDictionaryWriter.CreateBinaryWriter(stream))
 			{
-				formatter.Serialize(stream, this);
-				stream.Flush();
+				serializer.WriteObject(writer, this);
+				writer.Flush();
 			}
 		}
 
 		public static KdTree<TKey, TValue> LoadFromFile(string filename)
 		{
-			BinaryFormatter formatter = new BinaryFormatter();
+			var serializer = new DataContractSerializer(typeof(KdTree<TKey, TValue>));
 			using (FileStream stream = File.Open(filename, FileMode.Open))
+			using (var reader = XmlDictionaryReader.CreateBinaryReader(stream, XmlDictionaryReaderQuotas.Max))
 			{
-				return (KdTree<TKey, TValue>)formatter.Deserialize(stream);
+				return (KdTree<TKey, TValue>)serializer.ReadObject(reader);
 			}
 
 		}
diff --git a/External/KdTree/KdTreeLib/KdTreeNode.cs b/External/KdTree/KdTreeLib/KdTreeNode.cs
index 41adac572..35672ddd7 100644
--- a/External/KdTree/KdTreeLib/KdTreeNode.cs
+++ b/External/KdTree/KdTreeLib/KdTreeNode.cs
@@ -2,10 +2,12 @@
 using System.Text;
 using System.Linq;
 using System.Collections.Generic;
+using System.Runtime.Serialization;
 
 namespace UnityEngine.ProBuilder.KdTree
 {
 	[Serializable]
+	[DataContract]
 	class KdTreeNode<TKey, TValue>
 	{
 		public KdTreeNode()
@@ -18,11 +20,16 @@ public KdTreeNode(TKey[] point, TValue value)
 			Value = value;
 		}
 
+		[DataMember]
 		public TKey[] Point;
+		[DataMember]
 		public TValue Value = default(TValue);
+		[DataMember]
 		public List<TValue> Duplicates = null;
 
+		[DataMember]
 		internal KdTreeNode<TKey, TValue> LeftChild = null;
+		[DataMember]
 		internal KdTreeNode<TKey, TValue> RightChild = null;
 
 		internal KdTreeNode<TKey, TValue> this[int compare]