diff --git a/src/seedu/addressbook/ui/Gui.java b/src/seedu/addressbook/ui/Gui.java
index 20a7833c1..ed21989a4 100644
--- a/src/seedu/addressbook/ui/Gui.java
+++ b/src/seedu/addressbook/ui/Gui.java
@@ -36,7 +36,12 @@ public void start(Stage stage, Stoppable mainApp) throws IOException {
 
     private MainWindow createMainWindow(Stage stage, Stoppable mainApp) throws IOException{
         FXMLLoader loader = new FXMLLoader();
-        loader.setLocation(Main.class.getResource("ui" + File.separator + "mainwindow.fxml"));
+
+        /* Note: When calling getResource(), use '/', instead of File.separator or '\\'
+         * More info: http://docs.oracle.com/javase/8/docs/technotes/guides/lang/resources.html#res_name_context
+         */
+        loader.setLocation(Main.class.getResource("ui/mainwindow.fxml"));
+
         stage.setTitle(version);
         stage.setScene(new Scene(loader.load(), INITIAL_WINDOW_WIDTH, INITIAL_WINDOW_HEIGHT));
         stage.show();