diff --git a/classes/Language.php b/classes/Language.php
index d3edb9883..5cff87e0d 100644
--- a/classes/Language.php
+++ b/classes/Language.php
@@ -190,11 +190,14 @@ class LanguageCore extends ObjectModel
 		return $themes;
 	}
 
-	public function add($autodate = true, $nullValues = false)
+	public function add($autodate = true, $nullValues = false, $only_add = false)
 	{
 		if (!parent::add($autodate))
 			return false;
 
+		if ($only_add)
+			return true;
+
 		// create empty files if they not exists
 		$this->_generateFiles();
 
@@ -681,7 +684,7 @@ class LanguageCore extends ObjectModel
 		return Tools::generateHtaccess();
 	}
 
-	public static function checkAndAddLanguage($iso_code, $lang_pack = false)
+	public static function checkAndAddLanguage($iso_code, $lang_pack = false, $only_add = false)
 	{
 		if (Language::getIdByIso($iso_code))
 			return true;
@@ -703,7 +706,7 @@ class LanguageCore extends ObjectModel
 		else
 			return false;
 		
-		if (!$lang->add())
+		if (!$lang->add(true, false, $only_add))
 			return false;
 
 		$flag = Tools::file_get_contents('http://www.prestashop.com/download/lang_packs/flags/jpeg/'.$iso_code.'.jpg');
diff --git a/classes/Translate.php b/classes/Translate.php
index cd4ae4214..c98be204f 100644
--- a/classes/Translate.php
+++ b/classes/Translate.php
@@ -53,7 +53,8 @@ class TranslateCore
 			$iso = Context::getContext()->language->iso_code;
 			if (empty($iso))
 				$iso = Language::getIsoById((int)(Configuration::get('PS_LANG_DEFAULT')));			
-			include_once(_PS_TRANSLATIONS_DIR_.$iso.'/admin.php');
+			if (file_exists(_PS_TRANSLATIONS_DIR_.$iso.'/admin.php'))
+				include_once(_PS_TRANSLATIONS_DIR_.$iso.'/admin.php');
 		}
 
 		if (isset($modules_tabs[strtolower($class)]))
diff --git a/install-dev/models/install.php b/install-dev/models/install.php
index 036fc3980..dd268f93f 100644
--- a/install-dev/models/install.php
+++ b/install-dev/models/install.php
@@ -307,7 +307,11 @@ class InstallModelInstall extends InstallAbstractModel
 			if (!$xml = @simplexml_load_file(_PS_INSTALL_LANGS_PATH_.$iso.'/language.xml'))
 				throw new PrestashopInstallerException($this->language->l('File "language.xml" not valid for language iso "%s"', $iso));
 
-			Language::downloadAndInstallLanguagePack($iso, _PS_INSTALL_VERSION_);
+			if (InstallSession::getInstance()->safe_mode)
+				Language::checkAndAddLanguage($iso, false, true);
+			else
+				Language::downloadAndInstallLanguagePack($iso, _PS_INSTALL_VERSION_);
+
 			if (!$id_lang = Language::getIdByIso($iso))
 				throw new PrestashopInstallerException($this->language->l('Cannot install language "%s"', ($xml->name) ? $xml->name : $iso));
 			$languages[$id_lang] = $iso;
@@ -601,20 +605,19 @@ class InstallModelInstall extends InstallAbstractModel
 	 */
 	public function installModules($module = null)
 	{
-		if (InstallSession::getInstance()->safe_mode)
-			return true;
-
 		$modules = $module ? array($module) : $this->getModulesList();
-		$addons_modules = $this->getAddonsModulesList();
-
-		foreach($addons_modules as $addons_module)
-			if (file_put_contents(_PS_MODULE_DIR_.$addons_module['name'].'.zip', Tools::addonsRequest('module', array('id_module' => $addons_module['id_module']))))
-				if (Tools::ZipExtract(_PS_MODULE_DIR_.$addons_module['name'].'.zip', _PS_MODULE_DIR_))
-				{
-					$modules[] = (string)$addons_module['name'];//if the module has been unziped we add the name in the modules list to install
-					unlink(_PS_MODULE_DIR_.$addons_module['name'].'.zip');
-				}
-				
+		if (!InstallSession::getInstance()->safe_mode)
+		{
+			$addons_modules = $this->getAddonsModulesList();
+		
+			foreach($addons_modules as $addons_module)
+				if (file_put_contents(_PS_MODULE_DIR_.$addons_module['name'].'.zip', Tools::addonsRequest('module', array('id_module' => $addons_module['id_module']))))
+					if (Tools::ZipExtract(_PS_MODULE_DIR_.$addons_module['name'].'.zip', _PS_MODULE_DIR_))
+					{
+						$modules[] = (string)$addons_module['name'];//if the module has been unziped we add the name in the modules list to install
+						unlink(_PS_MODULE_DIR_.$addons_module['name'].'.zip');
+					}
+		}		
 		$errors = array();
 		foreach ($modules as $module_name)
 		{