Recently I encountered an issue with the WordPress custom-fields not working. I first did a Google search on “WordPress custom fields not working” and found information regarding extra lines in the functions.php file. I checked to make sure that I did not have any extra lines. I then checked my recent code changes and then checked disabling plugins. I then did a more thorough search on Google searching on “WordPress custom fields not working”, “WordPress custom fields broken” and the WordPress support forum. With my final search I found a post explaining that there is a known bug in 3.4.2 with custom fields and the add/update buttons.

Solutions to fixing WordPress Custom Fields Not Working

Add code snippet to your functions.php file:

function fix_custom_fields_in_wp342() { 

        global $wp_version, $hook_suffix; 

   if ( '3.4.2' == $wp_version && in_array( $hook_suffix, array( 'post.php', 'post-new.php' ) ) ) : ?>

<script type="text/javascript">

jQuery(document).delegate( '#addmetasub, #updatemeta', 'hover focus', function() {

jQuery(this).attr('id', 'meta-add-submit');

});

</script>

<?php

   endif;

}

add_action( 'admin_print_footer_scripts', 'fix_custom_fields_in_wp342' );

Install Hotfix plugin:
http://wordpress.org/extend/plugins/hotfix/