 <p>After the upload you can simply call <code>delete_transient( 'wc_attribute_taxonomies' );</code></p> <p>That's where the transients are created: <a href="http://oik-plugins.eu/woocommerce-a2z/oik_api/wc_get_attribute_taxonomies/" rel="nofollow">http://oik-plugins.eu/woocommerce-a2z/oik_api/wc_get_attribute_taxonomies/</a></p> <p>See also: <a href="http://wordpress.stackexchange.com/questions/119729/create-attribute-for-woocommerce-on-plugin-activation">http://wordpress.stackexchange.com/questions/119729/create-attribute-for-woocommerce-on-plugin-activation</a></p>