Arduino IDE and El Capitan

It is high time that the Arduino team addresses the issue with the IDE not seeing the serial ports in OS X El Capitan. There are innumerable blog posts about this over the internet, since the late 2015. There are multiple apocryphal workarounds, most of them with unpredictable consequences on the system, and mostly ineffective. I have six original Arduino UNOR3, which I have bought under the marketing statements that they could be programmed with MAC-OSX. The IDE is represented as "for MAC-OSX lion or later", while in fact it simply does not accomplish the most important task, i.e. connecting to the board under El Capitan. I understand that the software is open source, take it or leave it, but the boards are bought with real money under the false advertisement listed above. The Arduino team should have this as a major priority.
Giuseppe

I was curious about this because I like to run a version or 2 before the latest OS. I downloaded and installed the Arduino IDE version 1.6.8 on my wife's El Capitan Mac. I connected a clone Uno, which has the ATmega16U2 USB-to-serial chip. It worked immediately with no problem at all. I didn't even need to install a driver.

I think a lot of the problems people talk about are with trying to use derivative boards, such as those with CG340G chips.

I use Arduino Uno R3 original

My MAC: OS X 100.11.4 El Capitan
My IDE 1.6.9
On the Tools/serial menu I only see dev/cu/Bluetooth-incoming-Port
I have tried disabling kext in CSRUTIL
I have tried installing the drivers for CH340x after that
Nothing worked. Still cannot use my Arduinos.

Why would you attempt to use CH340x driver? There has never been an original Arduino board made with a CH340G chip.
I recommend uploading a picture of your board so we can see what you are talking about.

Here are the photos, if that is what you meant. Any suggestion would be welcome

It looks like an arduino.org board to me. I believe it should work with the arduino.cc IDE, although it would not be guaranteed to. I don't know about the hourly build and have not installed it before, but I have not seen complaints on the forum about it not working with an Uno.
What are the choices you see in the Tools, Port menu when you connect the Uno? What do you see in the Mac System Information application under the USB Device Tree? Here is what mine shows:

shot1.png

shot1.png

Here is what I see. Pretty desolate. Not that all worked until the latest MAC OS update.

Screen Shot 2016-05-07 at 4.42.13 PM.png

Screen Shot 2016-05-07 at 4.48.07 PM.png

Composite Device by ATMEL is the DFU bootloader. The board manufacturer (presumably arduino.org) forgot to load the USB-to-serial firmware on the ATmega16U2 chip next to the USB port. So you have a defective board.

You can load the firmware yourself, it comes with the IDE installation.

You can load it via USB using a DFU uploader program called dfu-programmer, and in that case the file you will want to upload is in the /Applications/Arduino.app/Contents/Java/hardware/arduino/avr/firmwares/atmegaxxu2/arduino-usbserial directory and called Arduino-usbserial-atmega16u2-Uno-Rev3.hex

Or you can load it using an ISP programmer device or a working Arduino as ISP (using the ArduinoISP sketch), connected to the 2x3 ICSP header pins near the USB port, and in that case the file you will want to upload is in the /Applications/Arduino.app/Contents/Java/hardware/arduino/avr/firmwares/atmegaxxu2 directory and called Arduino-COMBINED-dfu-usbserial-atmega16u2-Uno-Rev3.hex

More info and the way I like to load the firmware:

Thank you! I have had this board for some time and it has worked until recently... I will try and upload the firmware, but maybe it is permanently damaged... But I truly appreciate the help.

That is interesting it worked before. I have wondered for a while how the firmware on the board could become corrupt or somehow get erased. That is puzzling. I have not had it happen to me, but there have been others who had to re-load the USB-to-serial firmware.