I too had this problem but reading through this form and some other forms I have solved the problem, the problem is that there is something within the first person and third person maps causing the crash I’m not 100% sure what they are but I know if you go into content and delete the first person’s last third person map you should be able to open up your project again without crash, if that didn’t work you might also have to go into your config and delete the first person / 3rd person maps as your start by default