Olvin

Servus Leberschnitzel, I had exactly the same problem with a CR-10 after updatig to new Marlin-version. The problem: Cura 3.4.1 (actually it's plugin "USBPrinting") is now trying to autodetect the bautrate (different to former versions) by sending gcode "M105" (request temperature) at different baudrates to the serial port. It expects at least 3 successfull response lines containing the string "ok T:" - but Marlin is only sending 1 line matching this string - containing all temps (i.e. "ok T:27.03 /0.00 B:26.91 /0.00 @:0 B@:0\n") The solution: Change file C:\Program Files\Ultimaker Cura 3.4\plugins\USBPrinting\AutoDetectBaudJob.py (or whereever your Cura Plugin-dir is located) line 63 from: if successful_responses >= 3: to if successful_responses >= 1: ...and restart Cura, which will then find the correct baudrate (propably 115200) and enable the serial communication