The port is busy , Please HELP

Projects General Guidance
1

i have this problem

Arduino: 1.8.8 (Windows Store 1.8.19.0) (Windows 10), Board: "Arduino/Genuino Uno"

Error opening serial port 'COM3'. (Port busy)
Error opening serial port 'COM3'. (Port busy)

how can i fix it and what does it mean?

Please help

2

Probably You have another window that uses the COM3. Either close that wndow or disconnect and reconnect the USB plug.

2 Likes
3

Possibly trying a different USB cord could help. If not, try reinstalling the drivers.

4

I also periodically have this issue with Arduino 1.8.8 portable, Windows 7 64 bit. https://www.arduino.cc/en/Guide/PortableIDE
Arduino 1.8.5 does not have this problem. I can run them both at the same time or just either one, the issue follows 1.8.8 but I can't comment on whether it's related to my portable installation.

My only fix so far is to close (if open) the serial monitor and try opening it repeatedly until it opens. Then it works to flash the sketch.

5

If using a usb hub, remove that too

6

For me, rebooting the PC fixes it.

Paul