Hello, I have been developing WP site for a long time and I only faced this problem once and believe it or not it happened when I updated one of my clients site to 3.8 It’s really very disappointing.
To solve this problem you’ve to write a simple code. Open wp-config.php file and after the php opening tag “<?php” add the following line
define('CONCATENATE_SCRIPTS', false);
This should solve your problem. [Moderator note: Please don’t ask people to contact you]