Avrdude: ser_open can t open device COM3: The system cannot find the file specified

My computer cannot detect my Arduino Uno anymore,

• Reset button- > L led light blinks and it turns on forever
• Arduino 1.6.5: Tools->Port (greyed out) I remembered that previously it wasn't like this
• Unable to upload any sketch codes into the Uno anymore
• The existing code uploaded onto the Uno is FastLED(FirstLight) and it will work on my LEDs when I plugged them in

I have tried to .... but none fix my issue

• Restart my computer
• Press the reset button on the Uno
• Using the device mananger to change COM ports
• Device manager -> Other devices -> (nothing about Arduino Uno is found here)
• Plugged Uno into another computer but still doesn't work
• Reinstalled IDE

Problem shown in sketch,

avrdude: ser_open(): can't open device "\.\COM3": The system cannot find the file specified.

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

asked Sep 6, 2015 at 12:31

2

I have experienced a similar issue after plugging in another Arduino device. I didn't set up my environment for a long time and thus forgot he iterates the COM-Index. Maybe this is too easy, but you didn't provide much information.

This solved my problem: Open Arduino application > Tools > Port > Change to the target Port

If you are unsure which port to choose from: (on Windows) Open Device Manager > Connections (COM & LPT) > Usb Serial Port (COM[x]) where "[x]" is the index you are looking for.

answered Aug 17, 2017 at 20:59

1

Try a different arduino w/ your first computer, see if that will work.

answered Sep 6, 2015 at 20:52

Beginner to Arduino UNO.  I am trying to upload a sketch but I get this error message:

avrdude: ser_open(): can't open device "\\.\COM3": The system cannot find the file specified.

1)  Are there software utilities out there that specialize in enumerating ALL "COM" ports and what is using them?

2)  What "file" can't the system find?

3)  What is ser_open( )?

4)  What path is being referenced by this syntax:  "\\.\COM7"?

I read somewhere that sometimes the "COM" port is virtual and if something gets corrupted then the COM port disappears (or something like that).

It displays this message whether or not the Arduino UNO board is plugged in or not.

I've tried:

1)  Unplugging and plugging the USB data cable.
2)  Pushing the reset button on arduino UNO in different combinations and at different times during the compile / upload process.
3)  Reinstalling the Arduino IDE / drivers / using the web version of the same as well.
4)  Combing google results for similar problems / Q&A.
5)  Working in Device Manager.  Device Manager can't detect the board.

The board does have indicator lights that light-up when it is powered on.

Arduino IDE shows an error:



An error occurred while uploading the sketch avrdude: ser_open(): can't open device "\\.\COM7": The system cannot find the file specified.

How can I solve it?

Answer

You should do a checklist in order to jump to a conclusion:

• Make sure that you connect Arduino to PC via USB cable

• Check if selecting right COM port on Arduino IDE. On Arduino IDE, Go to Tools Port

• Check if any other software is using the same serial port. Two softwares cannot use the same serial port at the same time

• If you have one more USB cable, replace USB cable and then try again

• If you have one more PC, connect Arduino to another PC and then try again

• Reset your PC and then try again

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