Upload fails if port is open in Serial Monitor of another window · Issue #586 · arduino/arduino-ide · GitHub
![Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it. Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it.](https://gyorgybalassy.files.wordpress.com/2020/10/arduino-port-properties.png)
Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it.
![Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it. Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it.](https://gyorgybalassy.files.wordpress.com/2020/10/arduino-port-settings.png)
Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it.
![Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it. Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it.](https://gyorgybalassy.files.wordpress.com/2020/10/arduino-serial-port-in-device-manager.png)
Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it.
![avrdude: ser_open(): can't open device "\\.\COM5": access denied. - Installation & Troubleshooting - Arduino Forum avrdude: ser_open(): can't open device "\\.\COM5": access denied. - Installation & Troubleshooting - Arduino Forum](https://europe1.discourse-cdn.com/arduino/original/4X/6/3/a/63a61243382b3de443cf81791219bf121cbc54cb.png)
avrdude: ser_open(): can't open device "\\.\COM5": access denied. - Installation & Troubleshooting - Arduino Forum
![Connect to a device over Serial COM Port on Windows 10 with WSL1 TTY devices with Windows Terminal and minicom - Scott Hanselman's Blog Connect to a device over Serial COM Port on Windows 10 with WSL1 TTY devices with Windows Terminal and minicom - Scott Hanselman's Blog](https://hanselmanblogcontent.azureedge.net/Windows-Live-Writer/Connecting-to-a-device-over-a-Serial-Por_115BB/image_0b37601e-8427-4349-adad-8d48d640910a.png)
Connect to a device over Serial COM Port on Windows 10 with WSL1 TTY devices with Windows Terminal and minicom - Scott Hanselman's Blog
![ESP32 & could not open port 'COM5': PermissionError(13, 'Access is denied.', None, 5) - espressif32 - PlatformIO Community ESP32 & could not open port 'COM5': PermissionError(13, 'Access is denied.', None, 5) - espressif32 - PlatformIO Community](https://community.platformio.org/uploads/default/original/2X/5/5274b3594ce67a69c4e18e17542bb48628341be8.png)
ESP32 & could not open port 'COM5': PermissionError(13, 'Access is denied.', None, 5) - espressif32 - PlatformIO Community
![Arduino Nano - "avrdude: ser_open():system can't open device "\\.\COM1": the system cannot find the file specified" - Stack Overflow Arduino Nano - "avrdude: ser_open():system can't open device "\\.\COM1": the system cannot find the file specified" - Stack Overflow](https://i.stack.imgur.com/cx8c7.png)
Arduino Nano - "avrdude: ser_open():system can't open device "\\.\COM1": the system cannot find the file specified" - Stack Overflow
![Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it. Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it.](https://gyorgybalassy.files.wordpress.com/2020/10/arduino-port-selection.png)
Can't open device "\\.\COM4": Access is denied error when uploading a sketch from Arduino IDE | I learned it. I share it.
![mac os - Why a Arduino UNO R3 board can use in Windows 10 but can't be used in My Macbook Air(M1)? - Arduino Stack Exchange mac os - Why a Arduino UNO R3 board can use in Windows 10 but can't be used in My Macbook Air(M1)? - Arduino Stack Exchange](https://i.stack.imgur.com/DRVGx.png)
mac os - Why a Arduino UNO R3 board can use in Windows 10 but can't be used in My Macbook Air(M1)? - Arduino Stack Exchange
![Hey my arduino uno keeps saying ser_open(): can't open device "\\.\COM5": access denied. Any idea why am I doing somthing wrong : r/arduino Hey my arduino uno keeps saying ser_open(): can't open device "\\.\COM5": access denied. Any idea why am I doing somthing wrong : r/arduino](https://i.redd.it/hey-my-arduino-uno-keeps-saying-ser-open-cant-open-device-v0-tuvu9i31ndfa1.jpg?width=4000&format=pjpg&auto=webp&s=d8ada0b9bfcff40724d2bf66d9662074f706cfe1)