diff --git a/OpenRA.FileFormats/Map/MapStub.cs b/OpenRA.FileFormats/Map/MapStub.cs
index 4ee22c8e15..f4fba25c6a 100644
--- a/OpenRA.FileFormats/Map/MapStub.cs
+++ b/OpenRA.FileFormats/Map/MapStub.cs
@@ -12,6 +12,7 @@ using System;
 using System.Collections.Generic;
 using System.Drawing;
 using System.Linq;
+using System.Security.Cryptography;
 
 namespace OpenRA.FileFormats
 {
@@ -45,10 +46,22 @@ namespace OpenRA.FileFormats
 			var yaml = MiniYaml.FromStream(Container.GetContent("map.yaml"));
 			FieldLoader.Load( this, new MiniYaml( null, yaml ) );
 			
-			Bounds = Rectangle.FromLTRB(TopLeft.X, TopLeft.Y, BottomRight.X, BottomRight.Y);
-			Uid = Container.GetContent("map.uid").ReadAllText();
+			Bounds = Rectangle.FromLTRB(TopLeft.X, TopLeft.Y, BottomRight.X, BottomRight.Y);
+            Uid = ComputeHash();
 		}
 
+        string ComputeHash()
+        {
+            // UID is calculated by taking an SHA1 of the yaml and binary data
+            // Read the relevant data into a buffer
+            var data = Container.GetContent("map.yaml").ReadAllBytes()
+                .Concat(Container.GetContent("map.bin").ReadAllBytes()).ToArray();
+
+            // Take the SHA1
+            using (var csp = SHA1.Create())
+                return new string(csp.ComputeHash(data).SelectMany(a => a.ToString("x2")).ToArray());
+        }
+
 		static object LoadWaypoints( MiniYaml y )
 		{
 			var ret = new Dictionary<string, int2>();
diff --git a/OpenRA.Game/Map.cs b/OpenRA.Game/Map.cs
index ff47fe1963..8ea8330004 100644
--- a/OpenRA.Game/Map.cs
+++ b/OpenRA.Game/Map.cs
@@ -225,7 +225,6 @@ namespace OpenRA
 
 			SaveBinaryData(Path.Combine(filepath, "map.bin"));
 			root.WriteToFile(Path.Combine(filepath, "map.yaml"));
-			SaveUid(Path.Combine(filepath, "map.uid"));
 		}
 
 		static byte ReadByte(Stream s)
@@ -308,20 +307,6 @@ namespace OpenRA
 			File.Move(filepath + ".tmp", filepath);
 		}
 
-		public void SaveUid(string filename)
-		{
-			// UID is calculated by taking an SHA1 of the yaml and binary data
-			// Read the relevant data into a buffer
-			var data = Container.GetContent("map.yaml").ReadAllBytes()
-				.Concat(Container.GetContent("map.bin").ReadAllBytes()).ToArray();
-
-			// Take the SHA1
-			using (var csp = SHA1.Create())
-				Uid = new string(csp.ComputeHash(data).SelectMany(a => a.ToString("x2")).ToArray());
-
-			File.WriteAllText(filename, Uid);
-		}
-
 		public bool IsInMap(int2 xy)
 		{
 			return IsInMap(xy.X, xy.Y);