I have IMAC and I tried to download the Big Sur. I got an error that most of them has already. So I didn't do anything. After I turn off the computer and turn on. It start to reboot. So It looks like booting Big Sur. So I was waiting. But now, I got black screen. And I tried Cmmd +R key to turn on the computer. And I start to install Big Sur. When it hit 13 minutes left, it said an error has occurred. It is it. I tried 10 times. but I cannot. I cannot turn back to previous version. When I turn on computer, it said there is no start up disk.
Please help. I tried disk utility first aid. And I deleted all my hard. but I cannot do anything. please help.
Please help. I tried disk utility first aid. And I deleted all my hard. but I cannot do anything. please help.