Very frustrated and would appreciate your help. Have wasted hours on this and cannot figure it out. I had this exact problem with an Uno R3 clone I bought off Amazon but decided maybe that was the problem and bought a genuine Arduino Uno R3 off the Arduino.cc website. Same problem. The root of the issue is this error message:
avrdude: stk500_recv(): programmer is not responding
Before anyone asks, yes I have followed all steps indicated in the troubleshooting page.
I have searched the forum as well as StackOverflow and general Google searches. Now that I know it's happening even with the brand-name Arduino board, I don't think it should be a driver issue, but could be wrong. I'm on a Mac Pro 2008 running 10.11.6. I can't upgrade to 10.12 as Sierra is not compatible with my model.
I have taken numerous support steps including trying different USB ports and cables, have tried both the web editor and the desktop IDE, have installed and uninstalled FTDI drivers (as well as the CH drivers when I was trying to troubleshoot the clone before buying this brand-name one).
I saw a post on StackOverflow that suggested hitting the RESET button at a very specific point during upload, and someone else suggested that the OP change the baud rate on avrdude but I am not sure what the proper baud rate would be if the one chosen by the web editor is not compatible.
Grateful for any helpful advice you can provide! Console output from web editor below:
arduino-builder/arduino-builder -compile -core-api-version 10611 -build-path /tmp/321683378/build -hardware arduino-builder/hardware -hardware arduino-builder/packages/cores -tools arduino-builder/tools -tools arduino-builder/packages/tools -built-in-libraries arduino-builder/latest -libraries /tmp/321683378/pinned -libraries /tmp/321683378/custom -fqbn arduino:avr:uno -build-cache /tmp -logger humantags -verbose=false -logger humantags /tmp/321683378/Blink Sketch uses 928 bytes (2%) of program storage space. Maximum is 32256 bytes. Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes. Flashing with command:/Users/bvogts/.arduino-create/arduino/avrdude/6.3.0-arduino9/bin/avrdude -C/Users/bvogts/.arduino-create/arduino/avrdude/6.3.0-arduino9/etc/avrdude.conf -patmega328p -carduino -P/dev/cu.usbmodem5D11 -b115200 -D -Uflash:w:/var/folders/_j/1_gr8ml13tnddwd38r9yd8gr0000gn/T/arduino-create-agent170244921/Blink.hex:i avrdude: stk500_recv(): programmer is not responding avrdude: initialization failed, rc=-1 Double check connections and try again, or use -F to override this check. avrdude: stk500_recv(): programmer is not responding avrdude done. Thank you.