USB serial ports not accessible RRS feed

  • Question

  • I'm trying to connect various usb-serial speaking devices to a machine in order to send/receive commands. These devices showup as COM ports but when anything tries to open them I get some form of access denied.

    - the devices+cables communicate fine with the same software on my surface,
    - the devices+cables communicate fine with a usb-boot windows on the same physical machine,

    Fast repro:

    # assuming the device *is* COM5
    python -c "import serial; serial.Serial('COM5', 115200)"
    serial.serialutil.SerialException: Cannot configure port, something went wrong. Original message: PermissionError(13, 'A device attached to the system is not functioning.', None, 31)

    Or with go:

    // golang
    package main
    import ""
    func main() {
      c := &serial.Config{Name: "COM5", Baud: 115200}
      if s, err := serial.OpenPort(c) {
    // panic: A device attached to the system is not functioning.

    This appears to be a driver problem, but I can't for the life of me figure out how to figure out which one.

    • Edited by quietbrit Tuesday, May 7, 2019 11:16 PM
    Tuesday, May 7, 2019 11:12 PM