Two days ago, everything was fine. I could run NodeMCU-PyFlasher-1.0.0.exe and flash firmware onto nodeMCU boards (WeMos D1 mini or NodeMCU boards).
Today I wanted to re-flash a board. When I started NodeMCU-PyFlasher-1.0.0.exe the exe terminated itself after a few seconds! Huh? How could this be? What the heck could be the reason for this?