My visual editor has not worked for sometime. Don’t exactly know from which update. It at least did not work in 3.5.1 and 3.5.2.
Did some googleing and found several posts with many solution, but none of them worked for me.
Tried adding the line to wp-config.php:
define( ‘CONCATENATE_SCRIPTS’, false );
Cleared browser cache and logged in again. Didn’t work.
Next I tried was to delete my wp-includes folder and then copying it back from the tar.gz installation file. Edited a post and did a page refresh. Then the editor worked again.
Not sure excatly what was wrong, but at least now it’s working again and I didn’t have to do a full reinstall of WP.