[pitchie]

OK, I uninstalled and reinstalled 10.3.3 drivers to the best of my ability, as per Avid's instructions. (I was surprisingly unable to find DAE, DigiSetup and Pro Tools prefs, not to mention a Library folder inside my User folder—is that a mistake on their end or mine? I see the regular Library folder for my main drive and the one in the System folder. They say to go to users/username/library/prefs/...) Anyway, Pro Tools still runs fine as always. My hunch is that the MBox 2 Pro is fine because not only does it still work OK on my older Mac, but I borrowed someone else's MBox 2 Pro and had the same issue. It can happen upon firing up an external drive or even disconnecting it. I will continue to test today!