Hard Reset / Serial Monitor blocks USB-Port


yesterday i change my project to view data via Serial Monitor.
Now i can’t get any communication to the board (Mega) because
the USB is always busy by der Serial Monitor. I need a real Hard Reset
to erase the program from my Arduino.

Is there any chance to do it? Or does anyone have another idea?

I tried Mac & Linux Systems without any success…

Many Thanks in advance.

If you want to erase the program sending the serial data you can just do this:

  • File > New
  • Sketch > Upload

That just replaces it with a minimal sketch that does nothing and prints nothing to Serial.


thanks for the answer. Unfortunately i have no communication to the Arduino since the Serial Monitor is running on it.

None of my systems show the board in the List.

Printing to the serial monitor should not have any possibility of interfering with an upload since the Arduino is reset before the upload begins, which stops your program from running.

What do you mean by "None of my systems show the board in the List"? Are you saying the board's port doesn't appear in the Arduino IDE's Tools > Port menu? That doesn't make sense as the Serial Monitor won't work unless there is a serial port to connect to.

Yes, exactly. The board does not appear in Port menu. the only choice is a Bluetooth incomming port on my MAC.

My UNO board appears directly after connecting it and so did my MEGA board since yesterday ...

But maybe there is a diffenrent problem with the board that came up at the same time i started the Serial Monitor.

The problem ist fixed! It was really a hardware failure...

Thanks for the support!!!