Thanks kenta2, this works. However it confirms my opinion that there must be something wrong with these compressed .exe files.

There is another problem: the newer versions of GM are not able to load a very large PNG from MOBAC. "very large" means a 75GB PNG file which results in a 150GB tmp file of GM. Last version that works withput problems is 16.0. Up to 16.2 there are still good chances for success. With ver.17 its almost impossible. It starts fine, but after a while the whole computer slows down and becomes unusable in the end because even the mouse sticks. I suspect parallel code in GM and/or energy saving mechanisms in my laptop to be responsible for that. Its written in the new features of ver.17: "Dramatic Speed Improvements - depending on data and machine anywhere from 5 to 10 times faster for all types of data processing and rendering". From that I conclude that they are using a new library for all these tasks. I did tests with unregistered and patched versions, there is no difference.