Hi rw1644h,
Try searching through <a href="http://www.ni.com/support" target="_blank">ni.com/support</a> to see if any KnowledgeBases or other members of the community have had this issue. I searched for "AT-MIO-16E-10 Device Manager" and found this:
KnowledgeBase 3DEH4PNQ: Why Does My AT/ISA DAQ Board Show Up As Two Devices Under Device Manager?
<a href="http://digital.ni.com/public.nsf/allkb/BEA6B2841A42D22986256F10007F09CC" target="_blank">http://digital.ni.com/public.nsf/allkb/BEA6B2841A42D22986256F10007F09CC</a>