Ahoy Colleagues,
It's possible I'm the only person on the planet to have run into this problem but if any of you also have done so and are still struggling, the following may prove helpful...
Inexplicably, a couple of days ago Windows started blocking SH4.exe from execution. It would show a seriously red headlined pop-up with a warning and the disappointing advice that it would not launch SH4. This may have to do with a recent Windows security update. My anti-virus and anti-spyware confirmed no intrusions. I spent a highly frustrating day trying various Internet solutions including disabling the "hidden" UAC - all to no avail. What finally worked was to create an "elevated" shortcut with full privileges for SH4.exe, using the Task Scheduler as nicely described at the link below. There are quite a few steps but it's really easy. The author is to be commended for providing complete instructions:
https://winaero.com/blog/create-elev...in-windows-10/
This may be one of the few (or only) solutions that doesn't involve shutting down or otherwise compromising Windows security. It's specific to the application which is just what you want. The new shortcut has some mysterious useless icon but really, who cares? I'll figure out how to replace it one day.
Best wishes,
JHzlwd