remove all usb devices from your computer with the exception of the mouse and keyboard then see this document
after resetting the NVRAM boot normally and attach the USB device directly to the computer, not a hub or keyboard.
Sell magnetic stripe card reader writer, credit card reader writer, msr605, msr606, msrx6, msr x6, msr x6bt, msrx6bt, easymsr, easy msr, minidx3, mini dx3, MSR605X.
If this does not resolve the issue you will need to either resore your computer to the instance where the OS and the reader worked using a time machine backup if you have one, or you will need to determine the brand and model and find a suitable driver from the manufacturer if one exists. Alternately you can see if another card reader maker has a 10.11 compatible reader.
Apple is most certainly not going to intentionally try and fix this regardless of where the fault lies.
Feb 3, 2016 11:39 AM