To determine if the X-Cart code is the cause, or if the One Page Checkout is the cause, you can switch back and forth between the default multi-page checkout and the One Page checkout for your session only. This is done by adding &co_disable=Y to the end of the URL. Example: www..com/cart.php?mode=checkout&co_disable=Y You can then switch back to the One Page Checkout with this URL: www..com/cart.php?mode=checkout&co_disable=N Let’s say, for example, you are having trouble loading shipping methods. If they load correctly using the default X-Cart multi-page checkout, but not in the one page checkout, the issue is with your shipping setup. If you determine that the problem doesn’t exist in the default X-Cart checkout please contact alteredCart for support. If the issue is also present in the multi-page checkout, the issue is in your store configuration, or code. You will need to contact X-Cart support to fix this problem.