I have the same problem with these two boards: Ruggeduino (Uno compatible) and DFRobot Romeo 1 (Duemilanove compatible). On one of my Macs (a Macbook Pro running 10.11.4), I can see a new port /dev/cu.usbmodem641 or /dev/a4005g3t depending on the board. On the other computer (a Mac Mini late 2014), they just won't show. Same cable, same boards, and no hub. I don't know where to look to see an indication of a failure of some sort.

These two ones use a type-b USB socket (printer style)

Also on the Mac Mini that won't see any of those boards, I can connect an EtherMega2560 (Arduino Mega 2560) which happens to use a micro USB socket. I don't know if that is related to the problem.

Both computers run the same OS (OS X 10.11.4) and the latest version of Arduino.

Here is a difference (found in /var/log/system.log):

On the working computer:

Mar  3 22:20:42 pc101 kernel[0]: AppleUSBFTDI: fInBufPool,kMaxInBufPool 8,64 
Mar  3 22:20:42 pc101 kernel[0]: AppleUSBFTDI: Version number - 5.0.0, Input buffers 8, Output buffers 16

On the non working one:

cfprefsd[114]: BUG in libdispatch: 15E49a - 1718 - 0x0


  • 1
    If OS X has something like dmesg and lsusb (list USB devices) please post the output.
    – Avamander
    Commented Mar 3, 2016 at 21:04

1 Answer 1


My Ruggeduino stopped showing up as a serial device under El Capitan (10.11.6). I was able to fix this by installing/updating the VCP drivers for Silicon Labs USB devices available here:


After installing the Mac driver the Ruggeduino shows up as SLAB_USBtoUART and works fine with the Arduino GUI.

  • That would only help for a board with a silicon labs chip, but the documentation for the Ruggeduino seems to say it uses at ATmega16u for that role. It's pretty easy to look at a board and read what is on the chip, if it doesn't say SiLabs, this will not help. Commented Sep 18, 2016 at 6:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.