Diablo 4 update bug?

Hello, i played the diablo 4 through XGP, but always encountered a error which said “Diablo4 cant open a critical file”, I searched online which suggested me to delete the so called battlenet folder, but just successed once, now the method does not work anymore. i also dont think this is the way to solve it. i have no idea whether is this a bug or not. would you pls check it and fix it asap?