Salman, thanks for your reply but maybe I wasn’t clear: I am able to reset the Xiao as you suggest, but AFTER the code is successfully downloaded to the Xiao, I cannot use the Arduino Serial Monitor to debug the code because the Xiao serial port has ‘disappeared’. The only time it is available is for download, then it immediately goes away. On trying to invoke the Serial monitor, the Arduino IDE error says the port is not available. My code does use SerialUSB instead of Serial but it does not work because the Xiao is no longer presenting itself as a serial port. A double reset puts it in download mode, after download the port disappears; a single reset re-runs the downloaded code but it does not establish a USB serial port for the Serial Monitor to work. What am I doing wrong?