Yes! Duet 2 (USB) is fully compatible with Mac OS Mountain Lion (10.8). If Duet 2, May 2012 software was pre-installed before updating to OS X 10.8 Mountain Lion, it is not necessary to install any new Duet 2 software.

 

The Duet 2 July 2012 release Intended for first time Duet 2 installations on Mac OS X 10.7 Lion and 10.8 Mountain Lion.

Download July 2012 Software Installer (Mountain Lion Compatible)