Sorry, not sure what the problem would be... have you tried deleting the file and downloading it again? Sometimes that works. Or it might be your computer’s security settings: sometimes you can get around that by right-clicking and choosing Open. Hope this helps!
Sorry, wish I could help, but if what I mentioned in the previous post doesn't work, I'm not sure what else to try... I've had the same issue with other games when I'm trying to download them on spotty internet. Usually deleting the file and re-downloading will fix it.