WordPress 3.5 ‘Add Media’ button not working? Here’s a fix

For some reason WordPress 3.5 stopped allowing the ‘add media’ button to work. Even after using multiple browsers, deactivating all plugins, re-uploading the core wordpress files and reverting themes we still couldn’t get it to work.

Buried in the forums, we found a solution.

In your wp-config.php , add the line ‘define(‘CONCATENATE_SCRIPTS’, false );’

In other words, it used to look like;

/* Absolute path to the WordPress directory. */
if ( !defined('ABSPATH') )
 define('ABSPATH', dirname(__FILE__) . '/');

/* Sets up WordPress vars and included files. */
require_once(ABSPATH . 'wp-settings.php');

Now it should look like this;

/* Absolute path to the WordPress directory. */
if ( !defined('ABSPATH') )
define('ABSPATH', dirname(__FILE__) . '/');
 define('CONCATENATE_SCRIPTS', false );
 
/* Sets up WordPress vars and included files. */
require_once(ABSPATH . 'wp-settings.php');

Then just refresh your page, and add media button should work again.

Good luck!