Ok I validated your assumption by touching the cable close to the micro-USB connector and it lost connection immidiately. I changed the cable and it does not loose connection anymore. Nevertheless the cable I use now I tried before it didn’t work either at that point. I guess we are done. Thanks a lot for the intense support. Micro-USB is a dreaded connector.
Interesting point is: The COM-Ports of the Xavier show even when the Xavier Devkit is completely switched off. But also on Windows always 4 ports show.
