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

I tried to connect arduino uno after using arduino mega, changing the cable to the one I used with arduino mega solved the situation.

rupertschierz: in my case hepls: use another cable....

This was my case too

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.

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

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.

I was able to

  • End Process in task manager for avrdude.exe
  • Disable the com port to the arduino in device manager (triple low beep)
  • Enable com port to the arduino in device manager (low/high beep). 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.

Thank You, it solved my problem. Arduino Mega 2560

terry777: 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..

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.

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.

Actually agcsoft's link to the Chinese drivers was exactly what I needed Thanks a ton.

I encountered this error and something close to the error as in the following URL: 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.

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.

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

I tried all the solutions but none of them worked

TraumaER: 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.

[quote author=Coding Badly link=msg=3108711 date=1485801707] The usual culprit is a mobile phone / PDA application running in the background that constantly probes for a connected device.

[/quote] 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.

my was same problem yar

i just the change com pin also but it shows same error

my also showing same error and i try which u guys told but showing the same erro

TraumaER: 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'.

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.

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