Serial Monitor not reporting data

I am trying the very basic serial monitor example below. I have tried flashing with both OTA and USB CLI. Both seem to flash fine with Flash success! When I then run “particle serial monitor” I receive:

Opening serial monitor for com port: "/dev/tty.usbmodem14611"
Serial monitor opened successfully:

However, no data is ever printed. A “particle serial identify” results in “Serial timed out”.

Troubleshooting points: I am running macOS High Sierra on a new Macbook Pro. I have to use USB C dongles and have 2 different brands (Apple & Monoprice) Each generate a different address but all of the results from above are the same exepct for a /dev/tty.usbmodem1461 address for the Monoprice one.

Any suggestions? Thanks!

int counter = 0;

void setup() {

void loop() {
	Serial.printlnf("testing %d", ++counter);

Your code works like expected on my macOS High Sierra, Jimmy.

Check your USB-cable - there are different for (only) power and data transfer.

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