The software you are installing has not passed Windows logo testing to to verify its compatibility with Windows XP. I will continue to work with our team of engineering to get quickly out of information. » I also know that it is not convenient to downgrade your OS.
We recently released drivers for Eleven Rack, MBox 3 and C series interfaces, although I realize that helps you. 'I apologize for the delay on this, and I understand your frustration. I contacted Avid by e-mail and got this response from a real person. The only way I can use this box (the Fast Track Ultra) is to plug it into a PC or downgrade to previous OS X.
Fast Track Ultra has no official driver for 10.11.x and OS X is not directly recognize it either. BTW, there are no errors during installation. Re-installation of the drivers is not good. After the upgrade to El Capitan (10.11.2), my Fast Track Ultra no longer functions as an audio input/output device.
