diff --git a/addons/website_sale/controllers/main.py b/addons/website_sale/controllers/main.py
index 137f15b5782..b5083e3f7c6 100644
--- a/addons/website_sale/controllers/main.py
+++ b/addons/website_sale/controllers/main.py
@@ -390,13 +390,13 @@ class WebsiteSale(http.Controller):
                 return request.render('website.404')
             if abandoned_order.state != 'draft':  # abandoned cart already finished
                 values.update({'abandoned_proceed': True})
-            elif revive == 'squash' or (revive == 'merge' and not request.session['sale_order_id']):  # restore old cart or merge with unexistant
+            elif revive == 'squash' or (revive == 'merge' and not request.session.get('sale_order_id')):  # restore old cart or merge with unexistant
                 request.session['sale_order_id'] = abandoned_order.id
                 return request.redirect('/shop/cart')
             elif revive == 'merge':
                 abandoned_order.order_line.write({'order_id': request.session['sale_order_id']})
                 abandoned_order.action_cancel()
-            elif abandoned_order.id != request.session['sale_order_id']:  # abandoned cart found, user have to choose what to do
+            elif abandoned_order.id != request.session.get('sale_order_id'):  # abandoned cart found, user have to choose what to do
                 values.update({'access_token': abandoned_order.access_token})
 
         if order:
diff --git a/addons/website_sale/models/website.py b/addons/website_sale/models/website.py
index bc9c702760f..742e60c3d61 100644
--- a/addons/website_sale/models/website.py
+++ b/addons/website_sale/models/website.py
@@ -260,7 +260,8 @@ class Website(models.Model):
         sale_order = self.env['sale.order'].sudo().browse(sale_order_id).exists() if sale_order_id else None
 
         if not (sale_order or force_create or code):
-            request.session['sale_order_id'] = None
+            if request.session.get('sale_order_id'):
+                request.session['sale_order_id'] = None
             return self.env['sale.order']
 
         if self.env['product.pricelist'].browse(force_pricelist).exists():