diff --git a/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj b/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj
index 0ee62bda50..56e8a65815 100644
--- a/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj
+++ b/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj
@@ -617,6 +617,7 @@
     <Compile Include="Widgets\VqaPlayerWidget.cs" />
     <Compile Include="Traits\Render\WithInfantryBody.cs" />
     <Compile Include="UtilityCommands\CheckSequenceSprites.cs" />
+    <Compile Include="UtilityCommands\FixClassicTilesets.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <PropertyGroup>
diff --git a/OpenRA.Mods.Common/UtilityCommands/FixClassicTilesets.cs b/OpenRA.Mods.Common/UtilityCommands/FixClassicTilesets.cs
new file mode 100644
index 0000000000..6b0f95ce8b
--- /dev/null
+++ b/OpenRA.Mods.Common/UtilityCommands/FixClassicTilesets.cs
@@ -0,0 +1,104 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2015 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using OpenRA.FileSystem;
+using OpenRA.Graphics;
+using OpenRA.Traits;
+using StyleCop;
+
+namespace OpenRA.Mods.Common.UtilityCommands
+{
+	class FixClassicTilesets : IUtilityCommand
+	{
+		public string Name { get { return "--fix-classic-tilesets"; } }
+
+		[Desc("Fixes missing template tile definitions and adds filename extensions.")]
+		public void Run(ModData modData, string[] args)
+		{
+			// HACK: The engine code assumes that Game.modData is set.
+			Game.ModData = modData;
+			GlobalFileSystem.LoadFromManifest(Game.ModData.Manifest);
+
+			var imageField = typeof(TerrainTemplateInfo).GetField("Image");
+			var pickAnyField = typeof(TerrainTemplateInfo).GetField("PickAny");
+			var tileInfoField = typeof(TerrainTemplateInfo).GetField("tileInfo", BindingFlags.NonPublic | BindingFlags.Instance);
+			var terrainTypeField = typeof(TerrainTileInfo).GetField("TerrainType");
+			var terrainLeftColorField = typeof(TerrainTileInfo).GetField("LeftColor");
+			var terrainRightColorField = typeof(TerrainTileInfo).GetField("RightColor");
+			var empty = new Size(0, 0);
+			var single = new int2(1, 1);
+
+			foreach (var t in Game.ModData.Manifest.TileSets)
+			{
+				var ts = new TileSet(Game.ModData, t);
+				var exts = new[] { "" }.Concat(ts.Extensions);
+				var frameCache = new FrameCache(Game.ModData.SpriteLoaders, ts.Extensions);
+
+				Console.WriteLine("Tileset: " + ts.Name);
+				foreach (var template in ts.Templates.Values)
+				{
+					// Find the sprite associated with this template
+					foreach (var ext in exts)
+					{
+						Stream s;
+						if (!GlobalFileSystem.TryOpenWithExts(template.Image, new[] { ext }, out s))
+							continue;
+
+						// Rewrite the template image (normally readonly) using reflection
+						imageField.SetValue(template, template.Image + ext);
+
+						// Fetch the private tileInfo array so that we can write new entries
+						var tileInfo = (TerrainTileInfo[])tileInfoField.GetValue(template);
+
+						// Open the file and search for any implicit frames
+						var allFrames = frameCache[template.Image];
+						var frames = template.Frames != null ? template.Frames.Select(f => allFrames[f]).ToArray() : allFrames;
+
+						// Resize array for new entries
+						if (frames.Length > template.TilesCount)
+						{
+							var oldLength = template.TilesCount;
+							var ti = new TerrainTileInfo[frames.Length];
+							Array.Copy(tileInfo, ti, template.TilesCount);
+							tileInfoField.SetValue(template, ti);
+							tileInfo = ti;
+						}
+
+						for (var i = 0; i < template.TilesCount; i++)
+						{
+							if (template[i] == null && frames[i] != null && frames[i].Size != empty)
+							{
+								tileInfo[i] = new TerrainTileInfo();
+								var ti = ts.GetTerrainIndex("Clear");
+								terrainTypeField.SetValue(tileInfo[i], ti);
+								terrainLeftColorField.SetValue(tileInfo[i], ts[ti].Color);
+								terrainRightColorField.SetValue(tileInfo[i], ts[ti].Color);
+								Console.WriteLine("Fixing entry for {0}:{1}", template.Image, i);
+							}
+						}
+
+						if (template.TilesCount > 1 && template.Size == single)
+							pickAnyField.SetValue(template, true);
+
+						s.Dispose();
+					}
+				}
+
+				ts.Save(t);
+			}
+		}
+	}
+}