Hitting the back button after a batch process cause a nasty error
Here's a possible solution, however you'll need to alter the menu callback for patch and wrap the default page callback.

Create your hook_menu_alter() and change batch to be your own page callback function, and update the file attribute (unset if in your .module)

  // Default page for batch operations.
    $items['batch'] = array(
      'page callback' =&gt; 'system_batch_page',
      'file' =&gt; 'system.admin.inc',
    );


Basically your callback can mimic around the default system_batch_page() page callback. From there you can adjust what happens when someone hits an inactive or stale batch.