Mac(Catalina10.15.7) can't open device "/dev/cu.usbmodem14101": Resource busy


Arduino:1.8.16 (Mac OS X), ボード:"Arduino Uno"

     Using Port                    : /dev/cu.usbmodem14101
     Using Programmer              : arduino
     Overriding Baud Rate          : 115200

avrdude: ser_open(): can't open device "/dev/cu.usbmodem14101": Resource busy

avrdude done. Thank you.

Problem uploading to board. See for suggestions.


Do you have a terminal window already opened and using that port?

Yes, I have selected this from the terminal window.


Thank you.

I bought a regular ARDUINO UNO R3, but I get the same error.
This error seems to be the problem.

can't open device "/dev/cu.usbmodem14201": Resource busy

If you have any solution, please let me know.

After writing many times, I found that it was rarely successful.
I plugged in the USB cable while holding down the reset button and pressed reset for 10 seconds. I read the writing, so I tried it, but I feel that the success rate will increase a little.
Sometimes I get an error even after writing 100 times, and sometimes I succeed in the third time.
If the writing is successful, disconnect the USB and use an external power supply to operate.

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