avrdude: ser_open(): can't open device "\\.\com3":

Hi,

here is my situation - I got my first Arduino(Uno) last week. I successfully uploaded and ran quite a few programs on it. Only today when I connected it to my computer, I got this error-avrdude: ser_open(): can't open device "\.\com3": the system cannot find the file specified....

The "port" under tools menu is grayed out, even with the board connected. It used list COM3, if I had the board connected before. Now I can't find the Arduino in the device manager either!

I was working on an obstacle avoiding bot, and I uploaded a code for it last night. When I connect the Arduino to my computer, the power LED glows and that code runs. I wanted to change the code a bit tonight, but couldn't because of this problem.

I am running 64 bit Windows 8.1. My brother has the same OS. After some frustration with this, I connected the Arduino to his laptop for the first time only to get more frustrated - its the same problem there. No drivers start getting installed, the device manager doesn't show any new devices. It's as if the computers don't know if anything got connected to them!

I hope I could make my problem clear. Any help would be greatly appreciated. As I already said, this is my first Arduino, so you can assume I have virtually no experience with micro-controllers before.

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Is there anything other than the computer connected to the board? For example the robot?

I've tried plugging it to the computer keeping it connected to the robot, and also without keeping it connected to anything else. When I have the robot connected I can see the last program running (the motors turn the way they should). But in either case the computer doesn't recognize anything new plugged to it.

OK... Do you know what USB to serial chip it has? It is the one closest the USB to serial port. If you can't tell post a picture of the board or a link to where the board came from.

This is where I got it from - https://www.techshopbd.com/product-categories/boards/1253/arduino-uno-r3-china-techshop-bangladesh

It is an UNO R3, so is it supposed to be 16u2? I think I can faintly read 16u2 on the chip.

After looking up a bit, I found this - http://forums.adafruit.com/viewtopic.php?f=25&t=25146. So I tried following the instruction here - http://arduino.cc/en/Hacking/DFUProgramming8U2.

But now, when I run FLIP and try to select usb as my connection, I get a "atlibusbdfu.dll not found" error, although the file is there in both C:\Program Files (x86)\Atmel\Flip 3.4.7\bin and System32.

What do I do now? I am utterly clueless.

folks, I have the same problem. a months unable to alive arduino on my home comp. think problem is Win8.1 and driver. yesterday uploaded new driver 1.6.0, and first success. part. I am now testing 3 MEGA boards, 2 USB cables. problem is in COM ports, the same report. one board is running. on bottom status line is Arduino ... on COM4, Tools/Port says COM4, WIndows says Arduino on COM4. this one is working. Unplug and plug next MEGA : bottom status line : Arduino ...on COM4, Tools/Port says COM5, WIndows Arduino COM5. : can't open device "\.\COM4":
Unplug and plug next MEGA, result : bottom status line : Arduino ...on COM4, Tools/Port says COM3, WIndows Arduino COM3. : can't open device "\.\COM4":
switch off and on software, switch off and on windows don´t help, the same result.
how to match bottom status line and Tools/Port report?

Tested on another comp with XP, and next 3 MEGA boards . Result the same . One board have fit of bottom status bar : Arduino...on com4, and Tools/Port Com4. This one works. All next boards have another Tool/Port - com3, com5, com6, com7, while bottom status line show com4. And no one board response.
What to do?

When you disconnect and re connect a board you may need to re select a port in the IDE.

YES. Chilli, thanks. fix this is just click on Tools/Port info about port - this will match COM port in status line. this took me about 8 hours of testing = some days to find. hmmm

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peki:
YES. Chilli, thanks. fix this is just click on Tools/Port info about port - this will match COM port in status line. this took me about 8 hours of testing = some days to find. hmmm

I am pleased you know have it fixed...

I've got the same problem. It worked fine and then it stopped.
It says COM3 at the bottom of the IDE but get this error when I try to upload the file. The Com Port options are greyed out and so can't select it under TOOLS.
I'm still not sure what you did to fix this.
I'm running Windows 8.1 and Arduino IDE 1.6.1

I upgraded to IDE 1.6.3 and rebooted. When I ran the IDE, I had the COM3 under the Ports but as soon as I try to upload a file to the Arduino, i get the error and the Port selection grays out. even after shutting down and restarting, the Ports are grayed out.

UGH !!!

Never Mind......
There was a wiring error, shorting the Vcc. My Bad.
Note to self, "Check your hardware !!"

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Has anybody solved this problem?

I got almost an exact problem. But, mine is on Windows 7-32bit. I'm using arduino uno R3. The last time i use the board, it was fine. Today, i was just trying to blink an LED, but the program wont upload to the board and there's the message: "avrdude: ser_open(): can't open device "\.\COM3": The system cannot find the file specified."

Ports menu is greyed out. Device manager wont show anything connected, anywhere i plugged it wont be detected.

Had similar problem yesterday with my UNO R3. See my reply comment (#3 - FredKD) on "port selection in tools is grayed out". Once I refreshed my "ports" driver on my PC everything began running ok. I ran across a comment somewhere that said that, sometimes, communications with the Serial Monitor gets corrupted and may cause this "port" issue.

Guys, sorry to insist on the same issue, but I've tried pretty much everything in every forum or tutorial and no success.
I borrowed my brother's Arduino, actually Makerduino Uno V3, from Makerstudio. Their site says it uses FT232 instead of ATMega 16u2.
When I first plugged the board to my laptop, Windows 8.1 64 bits, it automatically completed the instalation and I was able to upload Blink. After disconnecting the board and reconnecting, it no longer worked. When I connect it, device manager shows 'FT232R UART' as an unknown device. If I install Arduino Uno R3 driver, or any other Arduino driver, it will give me an error message, device manager will show the yellow exclamation mark (as in attached pic1.jpg), and Arduino IDE Ports menu will appear grayed out (pic2.jpg). If I change the driver to FTDI, it won't show the error message or the yellow mark. Device manager will show USB Serial Port (pic3.jpg) and the port number will appear normally on Arduino IDE Ports menu (pic4.jpg). But it won't upload anything to the board! Now the error messages appear on the IDE, and are different when I try to upload a sketch (pic5.jpg) or the bootloader (pic6.jpg).

Could you, please, help?

Thanks!

Hello,
have you selected in Tools the type of the board?
(sorry for my English)

I am having the same problem with my Arduino UNO...it was working fine the first day I installed it, but then the next day my PORT was grayed out and when I tried to upload the sketch, the same error message appeared.
I think the problem lies with Windows 8. I found a u-tube video through another post that seems to temporarily work: Install the Arduino Uno under Windows 8 - YouTube
Basically you are tricking the computer to think your arduino is a modem...I have no idea how they figured that all out.
The problem is, I have to repeat this whole procedure every time I restart my computer. I switch to another COM # every time. I'm really hoping Windows 10 doesn't have this issue.

I purchased a "Genuine" Arduino Uno and played around with it, and did not have communication problems with it. I put it into a project while I purchased a replacement for it so that I could get it back, and, continue to experiment with it.
I bought the "replacement" Arduino from the same location that I bought my parts for the project. The replacement(s), an aftermarket Nano and ATMega2560 are both giving me "avrdude: ser_open(): can't open device "\.\COM3": The system cannot find the file specified."
Soooo, my questions are: (1) What file is it looking for?, and (2) Why does this problem still exist (since 2009)? Clearly I am not the first person to encounter this problem, but, I sit here researching this problem on the web, and in this forum for a solution, none of which seem to apply to my situation.
I am using a Dell laptop w/ Windows 7, Arduino IDE 1.6.5, and a Nano ATMega328 v3 compatible. I was simply trying to verify operational state before I substitute this device in place of my Uno. This device has never been tampered with by me. I just opened the ESD bag, plugged it into the computer/IDE and tried to load "Blink". I did identify the "board" and "processor" for the IDE, but, COM was (and still is) grayed out. It identified the connection as a "USB2.0-Serial" device on COM 3. No existing COM conflicts appear to exist. It does say the driver is not installed! Soooo, where is the driver?
I have tried every feasible driver search and install, to no avail. What do I do next?