DDJ RB ASIO not available anymore for headphone cueing

Hi there

My DDJ RB mixer has been working fine until I launched RekordBox today and found that the headphones were not cueing.  I went into my settings menu and DDJ ASIO was not selected under headphones output.  However, when I clicked on the drop down menu for headphones output it is no longer listed, even though it is still listed as a driver under audio?  Very strange.

Please help Pioneer, as I don't know what else to do.

Thanks