Something is wrong with the serial device. Either the driver was corrupted with the partial install or something else going on.
- power cycle the laser and reconnect in LightBurn. Capture all the data in Console window from the moment of reconnect. Copy and paste the text in a response here.
- open Device Manager in windows. Search for Device Manager if required. Expand the Ports node and take a screenshot.
- still in Device Manager, double click COM4, then select the Driver tab and take a screenshot
Device Manager will look something like this:
