OS X 10.x.x USB Issue Continue

[gLoeffler]

There is something wrong with how OS X communicates with the RUMBA Mega2560 board(s).

I have physical hardware that can dual-boot into Windows 7 and OS X 10.10.4 (tried 10.9.5, 10.10.2 also) from two physically different hard drives.

If I boot into Windows 7 (same physical hardware) ... with Repetier can connect to RUMBA board.

If I boot into OS X (again, same physical hardware) ... Repetier will NOT connect properly to the RUMBA board. If it does connect, it will stop printing shortly after starting a new print job.

NOTE: the RUMBA Mega2560 has the ATmega16u2 chip and NOT the FTDI chip ... so using the FTDI driver will not correct this issue since they are physically two different chips. I verified with visual inspection of the RUMBA board.

Suggestions...