error opening serial port"com5" (port busy)

Hi all,
When trying to upload a sketch to my Arduino UNO I get the above error message, how can the port be busy, if I am trying to up load through it? I have tried different ports and get the same message, my device manager states all com ports have up to date drivers, I have tried googleing and this forum but my problem seems slightly different to those already posted on this forum, or am I looking in the wrong place?

can anyone help me?

Arduino: 1.8.13 (Windows 10), Board: "Arduino Uno"

Sketch uses 11926 bytes (36%) of program storage space. Maximum is 32256 bytes.

Global variables use 602 bytes (29%) of dynamic memory, leaving 1446 bytes for local variables. Maximum is 2048 bytes.

Error opening serial port 'COM6'. (Port busy)

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x72

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x72

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x72

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x72

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x72

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x72

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x72

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x72

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x72

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x72

Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

gresleyman:
how can the port be busy, if I am trying to up load through it?

One possible cause is that sometimes a glitch will cause a port to get stuck open. The fix is to restart your computer.

gresleyman:
I have tried different ports and get the same message

Make sure you have selected the port of your Arduino board from the Tools > Port menu.

Sometimes the port will be labeled with the board name in the menu. Other times it will not. If you don’t know which port is your Arduino board, you can find it like this:

  • Unplug your Arduino board from the computer.
  • Tools > Port
  • Note the ports, if any, listed in the menu.
  • Close the Tools menu. The ports list is only updated when the Tools menu is re-opened, so this step is essential.
  • Plug your Arduino board into the computer.
  • Tools > Port - The new port listed in the menu is your Arduino board.

Hi Pert.

I have followed your steps 1 - 6 everything checks out as per your instructions, still no different com port busy?

I am running the Arduino IDE on a linux machine (ubuntu 18). When the IDE is running, Serial Monitor is open and I unplug an Arduino the USB0 port remains open and is not available any more. I must close the Serial Monitor window, go to Tools >> Ports to switch to the USB1 port, then I can upload again.

the serial port might be used by another application.
open the devices manager
expand the comports menu
existing ports will be listed.
unplug the arduino from PC port
the screen will refresh and you will see the serial port where the arduino is connected disapear.
reconnect the arduino.
screen will refresh again and you should see the right port.
select this port in the arduino IDE.

I get similar port errors in Arduino IDE if I have "Ultimaker Cura" running simultaneously. Cura obviously scans through USB-ports to find removable drives. And this is not visible in Windows Device Manager.

And I suppose there are many other apps doing the same thing.

5 Likes

Do you have anything connected to pin 0 and/or 1 on the UNO? If yes, disconnect it and try again.

Close the Serial Monitor.

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