wp_dropdown_categories links 404

Here is the answer I was looking for. Staring me right in the face.

I have managed to fix this issue with a simple addition to the code.

&value_field=slug

So final code which works and maybe of help in the future.

<form action="<?php bloginfo('url'); ?>/" method="get">
<label for="">Search.</label>

<?php
$select = wp_dropdown_categories(
'taxonomy=YOURTAXONOMY
&name=YOURTAXONOMY
&show_option_all=Please Choose...
&show_count=0
&orderby=name
&order=ASC
&echo=0
');

$select = preg_replace("#<select([^>]*)>#", "<select$1 onchange="return     this.form.submit()">", $select);
echo $select;
?>

<noscript><input class="rtd-btn primary" type="submit" value="View" />    </noscript>
</form>

Just change YOURTAXONOMY with your custom-taxonomy slug.

Hope this helps.