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Using Arduino => Installation & Troubleshooting => Topic started by: jordanthompson on Feb 08, 2011, 06:33 am

Title: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: jordanthompson on Feb 08, 2011, 06:33 am
HI all,
I am using the Arduino API (version 022?) with an Uno board.  It has been working fine for days...
I was playing with interrupt timers and have somehow gotten the board into a mode where I can't upload a new app.

I had an app that was blinking an LED every 6 seconds.
Now I want to upload a simple loop/sleep app and I get the following error:
Code: [Select]

avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.


I have tried rebooting my PC.
I have tried pressing the reset button for various durations, during reboot of the board, while it is running and even with no power applied same thing:
the green light goes on
the amber (L) and (TX) lights flicker and the API and Uno appear to work fine.  But then the LED on the Uno starts to blink every 6 seconds.
the (TX) amber light stays on
When this happens, the API's upload button turns orange and I get the above error.  The only way to clear the error is to unplug/plug the Uno.

Here is my new code (compiles fine):
Code: [Select]


void setup() {
  pinMode(7, OUTPUT);
}

// Main loop : empty but we have to have one...
void loop() {
  digitalWrite(7, HIGH);
  delay(1000);
  digitalWrite(7, LOW);
  delay(1000);
}


Thanks in advance for any help you can offer.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: jordanthompson on Feb 09, 2011, 04:38 am
* bump *
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: Coding Badly on Feb 09, 2011, 04:57 am
The first step is to verify the Uno is presented on COM3.  Remove the Uno.  Start Device Manager.  What serial ports are listed?  Insert the Uno.  Wait a few seconds.  What serial ports are listed?
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: jordanthompson on Feb 09, 2011, 05:32 am
WOW do I feel silly.  Somehow the board was changed from an Uno.  I changed it back to an Uno and it is working fine now.  I didn't even know this was an option, so I don't know how I did it.

thanks for your help.

Jordan
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: mellis on Feb 09, 2011, 03:14 pm
No worries.  Thanks for letting us know what was going on.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied. :
Post by: jhbower on Nov 18, 2013, 04:13 am
I see this was answered, or you figured it out, but here may be another cause/solution.

For back ground: I've been running this laptop fine with a Mega 2560, no problem at all.  I don't recall installing the drivers for it, but I must have done that. Now I try to hook up an Uno (and also a Due, and a Mega ADK for Android) and get driver errors (Win 7) for all of them. I also get the avrdude error above.

Apparently you may need to install additional drivers for the various boards. With your arduino board plugged in, click on the windows usb hardware button down on the taskbar, right click and select update driver, then direct it to your arduino drivers folder. Once windows knows there are arduino drivers there it seems to find the other boards without much help.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: nivesh on Sep 05, 2015, 09:03 am
Hi,
i just purchased an ezlcd 303 with Uno on it. There is no respond and handshake during test on Termie (code like CLS, PING) despite COM port, baud rate has been checked.

For IDE test i get the following error:
avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
 
Thanks.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: agcsoft on Nov 09, 2015, 12:33 am
The real problem is ..... "THE F.... DRIVER"

This works for my Arduino UNO and Nano, both Chinese generic

http://www.wch.cn/download/CH341SER_ZIP.html



Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: terry777 on Dec 19, 2015, 05:17 pm
solution!!!!
1. device manager
2. select ports
3. select port of arduino board examle : com1 ... com3 whatever it is
4. right click on com.
5. select properties
6. tab- port settings
7. click advanced
8. com port number- select new port number that is not in use.
9. confirm..
save and continue

the problem is a conflict between hardware devices, ie. the port is now used by another hardware device, mouse, ect..
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: rubikfast on Jan 14, 2016, 07:25 pm
THis is the Best Solution, So far ! And it Works !

http://www.fabrian.web.id/2016/01/uploading-sketch-problem-arduino.html
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: RoshanICV on Feb 26, 2016, 03:37 pm
Thanx Jordan!It worked succesfully exactly as per your instructions!!My UNO was not being detected in the computer..but after i disconnected the uno from the computer and reconnected it worked and succesfully loaded the program!(First Project) :)  :)
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: potatomagnet1 on Mar 09, 2016, 02:35 am
I'm also having this problem but i can't find the device manager anywhere.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: codlink on Mar 09, 2016, 03:07 am
I'm also having this problem but i can't find the device manager anywhere.
Please use your own thread, http://forum.arduino.cc/index.php?topic=384997.0 (http://forum.arduino.cc/index.php?topic=384997.0)
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: Kurius on Apr 06, 2016, 11:40 pm
@terry777 thank you! Your solution worked for me.  It was a COM port # conflict.  Changing the COM number did the trick!
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: RomeoDelta on Apr 23, 2016, 01:34 am
In my case, none of this worked. Turns out the problem was that Windows Update for Win10 "updated" my USB host controller and the new driver malfunctioned, but only in a few specific cases, the use of an Arduino Uno being one of them. The fix was to uninstall the driver and reinstall the manufacturer-supplied driver. Just one more thing to look at in the event you have this issue.

RD7
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: thehappyD on May 03, 2016, 05:26 am
I had the same problem with the UNO. I went to control panel->devices and printers. I right click on the Uno and seen that its showing incompatibility with USB 3.0. Even tho i know i have 1 usb2.0 port and 1 usb3.0 port, it showed the same issue for both ports. I went to my BIOS setting on my laptop and disabled USB3.0. I restarted my computer and it all worked out :)
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: rupertschierz on Nov 17, 2016, 04:02 pm
in my case hepls:
use another cable....
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: krossmaskinen on Dec 30, 2016, 01:55 pm
I hade the same issue. It was because RX and TX pins were plugged in to a wifi-module. Not sure why it's happening, but disconnecting the pins made it work again.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: old_codger on Jan 01, 2017, 06:17 pm
This is my first day with the Arduino.  Mine is a Kuman Uno, Christmas present 2017 :)

The COM port number was different but I had the same issues as most others on here.   I followed all the suggestions on the first page but it still came up with errors.  In the end I changed the Baud rate to 57600 and it worked.

It occasionally loses the plot but restarting the Arduino IDE software and unplugging and reconnecting the UNO seems to get it going again.

I'm really enjoying it.  It's been over 45 years since I did any real electronics, and I've haven't really done any programming before.

Only casualty so far is an LED.  I got creative and didn't put the resistor in the circuit correctly.  But Hey Ho, you can't make an omelette without breaking a few eggs :)

Hope this helps someone
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: NataliaDenisiuc on Jan 13, 2017, 01:22 pm
I tried to connect arduino uno after using arduino mega, changing the cable to the one I used with arduino mega solved the situation.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: kulibin17 on Jan 30, 2017, 07:56 am
in my case hepls:
use another cable....
This was my case too
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: hellored on Jan 30, 2017, 05:00 pm
Hi everyone i have the same problem with same message i tried changing the com to another and it worked for a few projects now i get the same message and i cant seem to find out what the problem is.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: Coding Badly on Jan 30, 2017, 07:41 pm

The usual culprit is a mobile phone / PDA application running in the background that constantly probes for a connected device.

Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: TraumaER on Feb 20, 2017, 06:54 am
Not sure if this will help anyone else, but with the 3d printer kit I purchased it had me install the Repetier Software which has a server and host component. The server was constantly connecting to the arduino and preventing me from being able to upload.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: tireblock on Mar 05, 2017, 01:44 am
I was able to
Upload was successful and stable.

As always, verify Arduino IDE|Tools|Board: and Port: are correctly selected (my board changed once, port becomes deselected occasionally)

If you go to C:\Program Files (x86)\Arduino\hardware\tools\avr\bin and can't delete avrdude.exe then it is probably still running and the process needs to be ended - I learned this by trying to delete the Arduino folder (to reinstall) but was unsuccessful because this program was still running.

This has been massively frustrating - Upon Sketch|Upload the avrdude.exe program should be killed automatically.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: kraizeg on Mar 05, 2017, 01:41 pm
Thank You, it solved my problem. Arduino Mega 2560


solution!!!!
1. device manager
2. select ports
3. select port of arduino board examle : com1 ... com3 whatever it is
4. right click on com.
5. select properties
6. tab- port settings
7. click advanced
8. com port number- select new port number that is not in use.
9. confirm..
save and continue

the problem is a conflict between hardware devices, ie. the port is now used by another hardware device, mouse, ect..
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: LordKelvin on Mar 21, 2017, 12:05 pm
Same problem here. I just needed to disconnect the RX and TX on D0 and D1 and it works. I just wanted to provide my feedback on this. I was looking for this too.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: raptor on Jun 11, 2017, 04:28 pm
I'm having a similar problem I'm trying to upload to, what I believe is a Chinese fake UNO R3.
Under tools the port option is visible but unavailable and I'm getting  (    avrdude: ser_open(): can't open device "\\.\COM3": The system cannot find the file specified.     )   for an error message. any advice would be great.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: raptor on Jun 11, 2017, 05:01 pm
Actually agcsoft's link to the Chinese drivers was exactly what I needed Thanks a ton.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: doronbehar on Jul 11, 2017, 10:55 pm
I encountered this error and something close to the error as in the following URL:
https://forum.arduino.cc/index.php?topic=28223.30
 (https://forum.arduino.cc/index.php?topic=28223.30)While my Uno was connected to pins tx and rx and while connected I tried to upload a sketch.

The assumed reason for it is the fact that these pins are able to load a bootloader to the Arduino and if they are connected, the board expects to be loaded with a bootloader.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: JacksonGee on Aug 03, 2017, 01:25 am
I've just had this same issue. Tried lots of the solutions above but the fix for me was unplugging a MTB GPS device that was on connected to my PC via USB. As soon as I unplugged that device everything worked fine.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: qwertyuiop12345 on Aug 16, 2017, 08:21 am
avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.


I tried all the solutions but none of them worked
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: TimK on Sep 13, 2017, 11:33 pm
Not sure if this will help anyone else, but with the 3d printer kit I purchased it had me install the Repetier Software which has a server and host component. The server was constantly connecting to the arduino and preventing me from being able to upload.
Thank you for your help !!! It was the guilty

I used Repetier server for long time, now I use Cura...

Thank because I was downcast. For others maybe you have a software like it.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: brice3010 on Nov 18, 2017, 01:59 pm
The usual culprit is a mobile phone / PDA application running in the background that constantly probes for a connected device.


I concur. I started with a new W7 64b prof computer, installed all drivers as they should be and were on the previous computers, yet same error as OP. i tried almost every trick described in the fora to no avail.

Until I found this comment. My mobile phone was indeed plugged in a USB socket. Removing it solved the issue.

EDIT: after removing the phone, uploading once (which gave no issue) and the reconnecting the phone on USB gave no further issues.

Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: vvvsk91 on Aug 09, 2018, 08:59 pm
my was same problem yar

i just the change com pin also but it shows same error
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: vvvsk91 on Aug 09, 2018, 09:10 pm
my also showing same error and i try which u guys told but showing the same erro
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: AlainF on Aug 14, 2018, 12:16 pm
Not sure if this will help anyone else, but with the 3d printer kit I purchased it had me install the Repetier Software which has a server and host component. The server was constantly connecting to the arduino and preventing me from being able to upload.
Dude, thank you! That was my issue too ! I opened the repetier-host application and did 'server->stop local server'.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: MartinLyne on Sep 13, 2018, 02:35 am
I just wanted to add something that worked for me: I turned on verbose output for upload, noticed it was overriding baud rate. I manually set the arduino baud rate to that desired baud rate in device manager and the upload then worked fine.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: fleury on Dec 06, 2018, 01:03 pm
J'ai connu ce problème. Il n' y a qu'une seule façon de le résoudre:
Supprimer Arduino
relancer l'ordi
réinstaller Arduino.
Cordialement
François
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: ivardahl on Feb 05, 2020, 09:40 am
There are LOTS of different reasons why this could happen. So, I thought I'd share one other possibility, which was the solution in my case:

I was developing my project on a barebone AtMega328p (chip in breadboard), and had worked on it for days, without problems. Then all of a sudden it throws the error message in question.
Turns out the boot loader was messed up. Burned a new boot loader, and got right back on track.

This could of course happen to any Arduino as well, not only the barebone setup that I was working on.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: Quintus26 on Feb 05, 2020, 12:35 pm
Hi,
i just purchased an ezlcd 303 with Uno on it. There is no respond and handshake during test on Termie (code like CLS, PING) despite COM port, baud rate has been checked.

For IDE test i get the following error:
avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
 
Thanks.
Chances are that your COM port is busy. Just detach any device that may be using it.
Title: Re: avrdude: ser_open(): can't open device "\\.\COM3": Access is denied.
Post by: kaakrc on Mar 20, 2020, 12:30 am
In my case, none of this worked. Turns out the problem was that Windows Update for Win10 "updated" my USB host controller and the new driver malfunctioned, but only in a few specific cases, the use of an Arduino Uno being one of them. The fix was to uninstall the driver and reinstall the manufacturer-supplied driver. Just one more thing to look at in the event you have this issue.

RD7
This worked for me. Go to the device manager and look for the device under "Ports". Right-click and uninstall the device and it will disappear. Then unplug the device and try again. It may tell you to restart your computer first. I have multiple USB ports that I use and I had to uninstall it for each one. Then once you plug back in, it installs the latest driver. You can also check sparkfun or similar for the latest drivers for either CH340 or the other FTDI chips.