Can't open COM4?

Development Tools IDE 1.x
1

Hello,

I am using an Arduino Uno R3 and am trying to upload a sketch to my Arduino, but I am getting this error message every time I try to upload:

"avrdude: ser_open(): can't open device "\.\COM4": Access is denied."

I've already checked the serial port and updated the drivers, as well as uninstalling and reinstalling the Arduino IDE.

How can I open the COM4 port and upload the sketch to my Arduino?

Thank you for the help

2

Is your Arduino definitely connected to COM4?

Have you looked in 'Device Manager' to see what it lists against COM4?
And look for an exclamation mark indicating a problem, too.

Have you tried rebooting?

Usually "Access Denied" means that the port is already open and in use, often by another device.

3

OldSteve:
Is your Arduino definitely connected to COM4?

Have you looked in 'Device Manager' to see what it lists against COM4?
And look for an exclamation mark indicating a problem, too.

Have you tried rebooting?

Usually "Access Denied" means that the port is already open and in use, often by another device.

The Arduino is definitely connected to COM4, I've rebooted as well, and also I've checked in device manager for any issues, and nothing seems to be wrong. Is there any other quick fixes that you think could be wrong with this issue?

Thank you

4

gaellington:
The Arduino is definitely connected to COM4, I've rebooted as well, and also I've checked in device manager for any issues, and nothing seems to be wrong. Is there any other quick fixes that you think could be wrong with this issue?

Thank you

You could perhaps try moving it to a different port in Device Manager. >Ports >Arduino UNO >Properties >Port Settings >Advanced