I have a CalDigit SuperSpeed Usb 3.0 Card in the PCIe slot 3 of my Mac Pro 2009 Quad Core Nehalem, with Mac OS X 10.6.6. The card is recognized in the System Profiler, but I am unable to install the "USB3_Driver_10_6_X_1.1.9" from the CalDigit Cd-Rom. The two packages IOUSBFamily_10_6 and CalDigitUSBcHCI_10_6 are grayed out in the "ad hoc setup" window, I cannot select them and if I press the "standard installation" button nothing happens: the "install button" is and stays grayed out. The driver package CalDigit_USB3_Driver_10_6_X_1.1.9 on my Cd-Rom is just 1.3 MBytes. There are no downloadable drivers from CalDigit's website. Do you have any suggestion or could you send me your Snow Leopard drivers to check if mine are corrupted?