Failed to autodetect serial port

I am having difficulty with Windows10 connecting to Lulzbot Mini. I have the same issue on two different machines, both Windows 10 (though the error is with different ports on either machine). In Cura I am able to click on Control, which brings up the Control menu. However at this point it fails to connect with the error. I click on the Connect button and it reinforces that there is an error:

_Changing monitoring state from ‘Offline’ to ‘Opening serial port’
Connecting to: COM3 with baudrate: 115200 (configured)
Unexpected error while connecting to serial port: COM3 ValueError: ‘Cannot configure port, some setting was wrong. Original message: WindowsError(31, ‘A device attached to the system is not functioning.’)’ @
Found no ports to try for auto detection
Changing monitoring state from ‘Opening serial port’ to ‘Error: Failed to autodetect serial port.’

I have tried to set the COM port manually as well as set the baudrate to AUTO as well as 9600. Nothing seems to work. I have verified that the drivers are installed.

Does anyone have any ideas of what I can try?

Thanks in advance,

Does the printer show up in Windows device manager when you connect the USB cable?

In Device Manager the only thing I see when the device is plugged in via USB is “Ports -> 3D Printer powered by Rambo”. I reinstalled the Cura software. I don’t see any other drivers installed and there doesn’t appear to be any errors.

The situation, however, is a bit more complicated. I was able to connect to the printer briefly. After multiple attempts I was able to update the Firmware to the very latest, however most attempts failed with a ‘Timeout’ about halfway through. Don’t ask why I tried to flash the Firmware. I have the impression that the USB connection is fickle. As I wiggled the USB cable it seemed to have more success connecting. I tried a different USB cord which initially appeared to have better success, but that was short lived. The whole USB connection may simply be a red herring, but if it is not I suspect that it is on the board itself. I was able to start a print job, however it was interrupted due to an error with the Print Head not being cleaned. Since then I have not been able to reconnect to the printer. Do you know if any command-line or utilities I can run to get a better idea of what the issue may be?


Did you clean your print head with a wire brush while the printer was on by any chance?

No. I am a bit of a newbie at this so I just let the print head clean itself. Still unable to get the printer to communicate with computer.

Update…I contacted support and they suggested to update to the latest version of Cura which must have been released fairly recently. So far things seem to work. I am keeping my fingers crossed.