[KevinH]

Okay, from comparing the crash logs to the good logs, there appears to be a missing Activation of the newly opened Sigil MainWindow. This activation happens right near the bottom of main.cpp.

The docs says that Windows can ignore this activation if for any reason it is in the middle of running a different process (Windows does not allow any interruptions).

So for some reason something else runs on your system in one configuration that does not in the other configuration. From the videos it appears that both your monitors are ASUS.

The ASUS Sound Studio 2 is a known program that interferes with Qt programs.

Are you absolutely positive that you are not running ASUS Sound Studio?

I can try to add a timer to try the activation again after a short delay. That might help.

Also please try rebooting into safe mode, with extensions off and see if the same strange issue still happens.