diff --git a/js/backend/products/product/product.general.js b/js/backend/products/product/product.general.js
index 29b70310f..261a05f40 100644
--- a/js/backend/products/product/product.general.js
+++ b/js/backend/products/product/product.general.js
@@ -124,8 +124,8 @@
                     var virtual_stocks = [];
 
                     $.each(sku_mod.stock, function(stock_id, stock_value) {
-                        var stock = that.stocks[stock_id];
-                        if (stock.is_virtual) {
+                        let stock = that.stocks[stock_id];
+                        if (stock && stock.is_virtual) {
                             virtual_stocks.push(stock);
                         }
                     });
@@ -1132,8 +1132,8 @@
                             }
                             sku_mod.stock[stock_id] = value;
 
-                            var stock = that.stocks[stock_id];
-                            if (stock.is_virtual) {
+                            let stock = that.stocks[stock_id];
+                            if (stock && stock.is_virtual) {
                                 virtual_stocks.push(stock);
                             }
                         });
diff --git a/js/backend/products/product/product.sku.js b/js/backend/products/product/product.sku.js
index ac8e87d59..335c000e3 100644
--- a/js/backend/products/product/product.sku.js
+++ b/js/backend/products/product/product.sku.js
@@ -2617,8 +2617,8 @@
                             }
                             sku_mod.stock[stock_id] = value;
 
-                            var stock = that.stocks[stock_id];
-                            if (stock.is_virtual) {
+                            let stock = that.stocks[stock_id];
+                            if (stock && stock.is_virtual) {
                                 virtual_stocks.push(stock);
                             }
                         });
@@ -3222,8 +3222,8 @@
                 var virtual_stocks = [];
 
                 $.each(sku_mod.stock, function(stock_id, stock_value) {
-                    var stock = that.stocks[stock_id];
-                    if (stock.is_virtual) {
+                    let stock = that.stocks[stock_id];
+                    if (stock && stock.is_virtual) {
                         virtual_stocks.push(stock);
                     }
                 });