It is now couple of times that I am running into this problem. I was working just fine with the board (e.g I was able to program and debug the board), until this afternoon. Now when ever I try to program my board, I am getting the following error:
Error: libusb_claim_interface() failed with LIBUSB_ERROR_ACCESS .
Error: unable to open ftdi device with vid 0403, pid 6010, description 'Dual RS232-HS', serial '*' at bus location '*'
But at the same time, in another terminal window, I am able to see print outs of my previous program being running on the board (I can see tty.usbserial-00001014B). The following is my ftdi setup:
Hossein@~/MyRepos/freedom-e-sdk ->kextstat | grep -i ftdi
152 0 0xffffff7f8330e000 0x7000 0x7000 com.FTDI.driver.FTDIUSBSerialDriver (2.3) ECC3AF36-431D-370D 86F2-5237785E9CF8 <99 41 5 4 3 1>
The interesting thing is that when I unload the FTDI driver and load apple driver using the following command:
sudo kextutil -b com.apple.driver.AppleUSBFTDI -p AppleUSBEFTDI-6010-1
I will be able to program the board but the serial port doesn’t show up in the /dev/tty.* 
So, I am kind of lost. This happened couple times before, but I managed to get it working by unload and loading the FTDI driver. But now, nothing works 
I have to mention that by default, I have setup FTDI driver to be picked up by osx and after a restart, the FTDI driver infact shows up. Also I am using openocd from homebrew. Here is my system information:
Hossein@~/MyRepos/freedom-e-sdk ->uname -a
Darwin MohammaseinsMBP 16.5.0 Darwin Kernel Version 16.5.0: Fri Mar 3 16:52:33 PST 2017; root:xnu-3789.51.2~3/RELEASE_X86_64 x86_64
Hossein@~/MyRepos/freedom-e-sdk ->brew list libusb
/usr/local/Cellar/libusb/1.0.21/include/libusb-1.0/libusb.h
/usr/local/Cellar/libusb/1.0.21/lib/libusb-1.0.0.dylib
/usr/local/Cellar/libusb/1.0.21/lib/pkgconfig/libusb-1.0.pc
/usr/local/Cellar/libusb/1.0.21/lib/ (2 other files)
/usr/local/Cellar/libusb/1.0.21/share/libusb/ (16 files)
Hossein@~/MyRepos/freedom-e-sdk ->libusb-config --version
0.1.12
Hossein@~/MyRepos/freedom-e-sdk ->openocd --version
Open On-Chip Debugger 0.10.0
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
Any suggestions??