Try out downloading and installing the UE4PrereqSetup_x64.exe and see if that fixes it.
Viewing post in Cactus (Prototype) jam comments
It seems like this is an issue with UE4's engine code and it won't be fixed until the next UE4 hotfix/release. https://forums.unrealengine.com/unreal-engine/feedback-for-epic/1758469-unreal-engine-4-25-and-windows-7-compatibility