New Mac OS X release has broken USB drivers. oh well.
https://www.mac-usb-serial.com
Yea… There are instructions for “making I work” but I have had mixed results. My 'duino restarts when I connect to it now (it did not before) and I could see that as a big problem when printing from sd.
Its really screwed up. I am sorry I upgraded the OS
@Matt_Harrington The reset-on-connect happens in Linux also (more accurately when host software opens the port). It is not a problem if you start your host software before initiating a SD card print. That is the way I do things.