I have an Arduino Nano and I’m trying to use it with Mac OS Yosemite (10.10). However, I’m having issues with the data transfer between the computer and the device. The Arduino is powered (LED is illuminated), however, I can’t upload anything to it. The serial port is not recognised and after installing a multitude of drivers, nothing seems to work.

Is there a specific driver or process I need to follow to enable data transfer?

  • Is this a genuine Arduino device, or a clone?
    – user7800
    Jul 30, 2015 at 7:03
  • It looks like a genuine device, but was very cheap and of poor quality - most likely a clone.
    – Rohan
    Jul 30, 2015 at 11:39

2 Answers 2


Setting kext-dev-mode=1 allows unsigned kernel extensions to load, which is not recommended, as it lowers OS X security.

Instead, try the signed 64-bit kernel extension from FTDI here: http://www.ftdichip.com/Drivers/VCP.htm , version 2.3, which does require changing OS security permissions.

  • In theory that one should be much better - but I cannot get it work. It keeps unloading the kext and nothing shows up under /dev. Works for you?
    – tcurdt
    Mar 18, 2016 at 10:45
  • 2
    This is only applicable to boards having an FTDI USB serial chip. It is not needed for boards using an ATmega16u2 and will not help with boards having a CH340/CH341. Jan 9, 2017 at 23:03

From this blogpost you can download signed macOS driver for CH340. Works fine on Sierra 10.12!

  • 1
    Without commenting on the legitimacy of the linked software, it should be noted that a CH340 driver will only work on boards using a CH340 or CH341 - it will not help for boards using an FTDI part or an ATmega16u2. Blind installation is probably not to be recommended. Jan 9, 2017 at 23:04
  • I think if this kext is signed by Apple, they trust it, aren't they?
    – kelin
    Jan 15, 2017 at 20:39
  • Regardless of who allegedly signed it, that driver will not help anyone who doesn't have a CH340/CH341 or functionally identical adapter. The actual Arduino Nano uses an FT232RL chip, requiring a different driver (which may well be built in). The point is to figure out what you have before installing drivers - this can be determined either by reading the part numbers or from the USB tab in system report. Jan 15, 2017 at 20:43

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