Mr. Kutchera,
We have an Avid CoreAudio Device and Avid MBox mini. The dongle is plugged in with a direct pathway to the computer systems. The Mac OS system works where the drivers are automatically installed with OS installation. As far as I can find, 10.10.5 of OS X Yosemite has no other drivers outside of the regular installation ones.
We have tried verifying and repair the disk locations of the various drives. We tested two different external drives and they had the same problem. We tried several drives on our school server and it has the same problem. We thought that maybe the Avid system had a corruption during download so I went and completely uninstalled Avid Media Composer and reinstalled it to see if that would help, but it did nothing. Mind you, we have the exact same set u on the other 22 IMac computers in this lab.