diff --git a/.htaccess b/.htaccess
index f1ef8719ba1a8421e3d58aeceee851da731e4f77..bd75f90396737c685c2f95e1c7424d52dc109144 100644
--- a/.htaccess
+++ b/.htaccess
@@ -170,6 +170,10 @@
 
 </IfModule>
 
+<IfModule mod_env.c>
+    SetEnv MAGE_MODE "developer"
+</IfModule>
+
 ############################################
 ## By default allow all access
 
diff --git a/app/code/Magento/Catalog/Model/Product/Attribute/Backend/Sku.php b/app/code/Magento/Catalog/Model/Product/Attribute/Backend/Sku.php
index 728cd250923fee5d7616e9958052d654a219f9f1..3da70506427f61f1f5b5e41451ff5e873c710852 100644
--- a/app/code/Magento/Catalog/Model/Product/Attribute/Backend/Sku.php
+++ b/app/code/Magento/Catalog/Model/Product/Attribute/Backend/Sku.php
@@ -55,7 +55,7 @@ class Sku extends \Magento\Eav\Model\Entity\Attribute\Backend\AbstractBackend
         }
 
         if ($this->string->strlen($object->getSku()) > self::SKU_MAX_LENGTH) {
-            throw new \Magento\Framework\Model\Exception(__('SKU length should be %1 characters maximum.', self::SKU_MAX_LENGTH));
+            throw new \Magento\Framework\Model\Exception((string)__('SKU length should be %1 characters maximum.', self::SKU_MAX_LENGTH));
         }
         return true;
     }
diff --git a/app/code/Magento/Cookie/Model/Config/Backend/Domain.php b/app/code/Magento/Cookie/Model/Config/Backend/Domain.php
index 2ef0961665d904e09eaca887960f969adef0759c..6bbb307f39ab57b1e829c7e4da514f4a4ca4d416 100644
--- a/app/code/Magento/Cookie/Model/Config/Backend/Domain.php
+++ b/app/code/Magento/Cookie/Model/Config/Backend/Domain.php
@@ -48,7 +48,7 @@ class Domain extends \Magento\Framework\App\Config\Value
         // Empty value is treated valid and will be handled when read the value out
         if (!empty($value) && !$this->configValidator->isValid($value)) {
             $msg = __('Invalid domain name: ' . join('; ', $this->configValidator->getMessages()));
-            throw new \Magento\Framework\Model\Exception($msg);
+            throw new \Magento\Framework\Model\Exception((string)$msg);
         }
     }
 }