Hi,
1. Do you still have a menu with the alias "checkout" ? If so, please delete it.
In Configuration > Checkout, do you have set a menu for the option "Force a menu on checkout" ?
If not, please set a menu there, else you can too edit the view "cart / showcart" and replace:
if(!empty($itemid_for_checkout)){
$url_checkout = hikashop_completeLink('checkout&Itemid='.$itemid_for_checkout);
}else{
$url_checkout = hikashop_completeLink('checkout'.$url_itemid);
}
By:
$url_checkout = hikashop_completeLink('checkout&Itemid=XX');
2. Please try to replace:
$url_checkout = hikashop_completeLink('cart'.$url_itemid);
To:
$url_checkout = hikashop_completeLink('cart&Itemid=XX');
Where "XX" need to be replaced by the id of the cart display menu. In your url you must only have "/cart" and not "/cart/cart" when clicking on the yellow/green cart symbol. If you still have "/cart/cart" so remove 'cart&' in the previous code.
ps: The issue is coming from your menu settings, you are using aliases already in use by default in HikaShop.