I have a custom post type "packages" with a taxonomy "Celebrations" that has a few terms in it.

When I try to add a link to my wp nav menu through Appearance > Menus and choosing the term I want from the Celebrations meta box, the item shows up red with a title "(Invalid)".

See here for what I'm seeing: http://screencast.com/t/cyGF0cJU8

Has anyone else had this problem before?

I used Custom Post Type UI to register the post type and taxonomies originally with no other problems. After this happened, I tried disabling that plugin and registering them manually, but to no avail.

I've taken a look at the wp core to see what makes this come up and this is what I found: includes/nav-menu.php L595 in wp_setup_nav_menu_item()

elseif ( 'taxonomy' == $menu_item->type ) {
            $object = get_taxonomy( $menu_item->object );
            if ( $object ) {
                $menu_item->type_label = $object->labels->singular_name;
            } else {
                $menu_item->type_label = $menu_item->object;
                $menu_item->_invalid = true;

All of the meta data for the menu item appears to be there: http://screencast.com/t/0hHQmObsQAT

Any help is greatly appreciated as always!

  • Please try the same with a custom registration (via code) instead and see if you still can reproduce the problem.
    – kaiser
    Commented Nov 26, 2015 at 11:39

2 Answers 2


Yeah I found the answer an another website. Taxonomies have a restriction that they cannot have uppercase characters in their name they can only have lowercase and underscore characters. that`s the problem.


I had the same problem, and it turned out to be a duplicate link that was already in the menu structure elsewhere. At least, that's my best guest why it was invalid. :-)

See also the source code here.

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