I use a Mac as my daily laptop. I sometimes have to console into really old Cisco devices. If you find that after updating to OSX El Capitan, your USB to Serial adapters aren’t showing up anymore, here is what you’ll need to do.
WARNING: This will disable the new Rootless protection.
OSX 10.11 has a new feature called “System Integrity Protection” that blocks any kind of third party driver from being used. This is also referred to as “Rootless”. This process will turn that off and allow you to run processes that can modify system files.
- Install your USB Serial adapter drivers if you haven’t already done so.
- Open a terminal and type
sudo nvram boot-args="kext-dev-mode=1 rootless=0"
- Open terminal with USB adapter attached and cd to /dev
- type ls and your adapter should show up like tty.usbserial.