Fix WordPress category (or other taxonomy) counts, after incomplete import, etc.

fix-category-counts.php

<?php

// Can drop into {yourtheme}/functions.php and then hit the site.

$update_taxonomy = 'category'; // Set to the correct taxonomy.

$get_terms_args = array(
	'taxonomy'   => $update_taxonomy,
	'fields'     => 'ids',
	'hide_empty' => false,
);

$update_terms = get_terms( $get_terms_args );
wp_update_term_count_now( $update_terms, $update_taxonomy );