Symfony2 : how to fix the “Warning: SessionHandler::read()” Exception

If you too you got an error like this one :

Warning: SessionHandler::read(): open(\xampp\tmp\sess_hagg7jkmp7l7fmh5ec4k6jmgu0, O_RDWR) failed: No such file or directory (2) in [...]\app\cache\dev\classes.php line 423

I let you know that you just have to add/change these 2 lines in app/config/config.yml to fix it :

        handler_id: session.handler.native_file
        save_path: "%kernel.root_dir%/sessions"