The Mbox3 is not the issue, it is Win10 which isn't supported yet, not PT12 nor the Mbox3 drivers so if i were you i would downgrade to Win8 and use the Mbox3 with Pro Tools 12 until Win10 is supported and working.
Here is a link for upgrade to PT12 if you have the qualifying products
http://www.sweetwater.com/store/detail/PT11LEup-e