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Reply to Big Sur crash restart loop after update
I had a similar problem on my MBP 16 after installing Big Sur (11.0.1) via Software Update. Endless kernel panics and reboots. Safe mode did not work. Weirdly, in Recovery mode I could not get the APFS disk mounted. The system volume reported "Sealed: Broken" and my user data was locked by FileVault and I could not unlockVolume. I also could not reinstall Big Sur, as the installer was unable to unlock the disk and reported an "unexpected error". (Same thing in Disk Utility when attempting First Aid) I took a bunch of steps, and am unsure which were the essential ones so I'm posting everything I did. Maybe this will help someone else. Reset SMC Booted into recovery mode [Unsure if useful] Attempted to use 3rd party APFS file recovery utility (iBoySoft), running: sh <(curl URL hidden Played around a bit with 3rd party tool but it didn’t work - it asked for password to unlock disk, but none I tried worked. In terminal, tried “resetpassword” - and selected forgot password. For the first time, it let me change the password for my user (admin) account. It had me authenticate via iCloud and sent a trusted device request/confirmation code, etc. It seemed to suggest I was changing the FileVault password. [Unsure if useful] Startup Security Utility (from pulldown menu in Recovery mode) now worked for the first time. I reduced security level to medium to boot any previously authorized OS Reinstalled Big Sur from recovery mode - it was now able to unlock the disk Reinstallation successful On first boot, Big Sur reported some 3rd party extensions were causing reboot and have been disabled. Based on others' experience, I'm guessing this was the cause of the previously encountered kernel panics (?) My best guess is that the essential steps were 1,2,5, maybe 6, and 7. Good luck
Nov ’20