Ursprünglicher Beitrag von: Jurgen ,
Ok, badda-frekkin-bing, as some would say. The random return to login screen was not as random as it appeared. Those returns were caused by dragging finger over the trackpad and causing the curser to go to the top left corner, where it triggered the return to login page. And that was so, because under Mission Control “Hot corners”were enabled for reasons unknown. Upon disabling this function, the problem was solved.