diff --git a/gtk-sharp/MapWindow.cs b/gtk-sharp/MapWindow.cs
index f048bdb..c6a2d3a 100644
--- a/gtk-sharp/MapWindow.cs
+++ b/gtk-sharp/MapWindow.cs
@@ -978,6 +978,7 @@ bool SaveAs() {
 	    d.CurrentName = Level.Name + ".sceA";
 	    d.DoOverwriteConfirmation = true;
 	    try {
+		Level.Validate();
 		if (d.Run() == (int) ResponseType.Accept) {
 		    mapfile = new MapFile();
 		    Level.AssurePlayerStart();
@@ -1014,6 +1015,7 @@ bool Save() {
 	    } else {
 		bool success = false;
 		try {
+		    Level.Validate();
 		    Level.AssurePlayerStart();
 		    Redraw();
 		    mapfile.Directory[0] = Level.Save();
diff --git a/level/Level.cs b/level/Level.cs
index 17e1601..a900aa8 100644
--- a/level/Level.cs
+++ b/level/Level.cs
@@ -347,6 +347,29 @@ public void AssurePlayerStart() {
 	    }	    
 	}
 
+	void ValidatePlatformTriggers() {
+	    for (int i = 0; i < Polygons.Count; ++i) {
+	        Polygon polygon = Polygons[i];
+		if (polygon.Type == PolygonType.PlatformOnTrigger || polygon.Type == PolygonType.PlatformOffTrigger) {
+                    bool found = false;
+	            foreach (Platform platform in Platforms) {
+	                if (platform.PolygonIndex == polygon.Permutation) {
+		            found = true;
+	                    break;
+	                }
+		    }
+	            if (!found) {
+	                string message = "Invalid map: Platform trigger at polygon " + i + " does not have a valid platform assigned.";
+	                throw new Wadfile.BadMapException(message);
+                    }
+	        }
+	    }
+	}
+
+	public void Validate() {
+	    ValidatePlatformTriggers();
+	}
+
 	public Wadfile.DirectoryEntry Save() {
 	    Wadfile.DirectoryEntry wad = new Wadfile.DirectoryEntry();
 	    wad.Chunks = Chunks;