grumpyduckman:
Very annoying. I followed the instructions and I can't see a reference to this problem. Some guidance please.
It drives you mad when seemingly simple stuff does not work, and it happened to me just now when using the ESP32.
The esptool.py error occurs when the ESP32 core cannot, for some reason, contact the serial port you have defined in the Arduino IDE.
Perhaps it should be mentioned in the instructions, but that would be something you should mention to Expressif, who produce the ESP32 core you are using, its not produced by Arduino.