[Obsidian Dragon]

With all this "back and forth" I have lost track if we've answered the original question from skystudios. There are official compatibility charts on the Avid website to help identify what version of Protools will work with what OS you intend to run. The link to the Mbox Mini Gen3 driver I provided earlier also lists the version of the OS that it works with.

I think the difficulty is that the Mbox series of interfaces were designed originally to work with Protools LE only (and serve as a form of copy protection). Unfortunately they were not fully ASIO compatible like many common audio interfaces are. When Protools 9 opened up to allow using non Avid/Digidesign Mbox interfaces, there was a shift to use ASIO compliant interfaces. Thus began the end of the Mbox product cycle.

Honestly, the Mbox interfaces were mediocre as best (I owned several), and almost any modern interface is better. I know you said that you got yours for free so I understand you want to get it to work. If you are willing to do your homework and accept the limitations (older OS, older version of Protools, older plugins, etc.) that is your choice.