Screen freezes if not manually refreshed

Good afternoon,

I’ve noticed that in Unreal 4 Engine based software the screen freezes completely, and doesn’t refresh until I manually refocus the window by Alt-tabbing, at which point 1 new frame is rendered and it freezes once again.

Maybe this isn’t the right place to ask but since it’s an engine rather than game specific engine I was hoping someone might know the solution to this problem.

Thanks in advance!