I am on a mac, and this the first time I've encountered this problem, more information would be helpful. Thank you.
Okay so, first u go to the apple icon on the top left of your screen, after you go to settings, should be the 2nd voice from the top, after you click on privacy and security, the name might not be completely the same but im translating from my italian pc, then once u clicked on that you scroll completely until you find a voice that will say something like: this game was blocked from opening because of... open anyways? and you will have a button saying open anyways. you click that and then there you have it. make sure that before you do all this you have opened the file and it told u that it couldn't be opened because ur pc cant verify it. If you have any more questions let me know.