Recently a colleague accidentally changed their Mac system settings
through /etc/synthetic.conf. This caused the collegue could not even
login into the Mac with any account.
We then found the following mac recovery steps from the Apple Website:
https://support.apple.com/en-us/102603
In case this page may disappear in the future:
- With Apple Silicon:
- Turn on your Mac and continue to press and hold the power button as your Mac starts up.
- Release the power button when you see the startup options screen, which shows your startup disks and a gear icon labeled Options.
- From this window you can start up from a different disk, start up in safe mode, use macOS Recovery, and more.
- With Intel-based Mac:
- Command (⌘)-R: Start up from the built-in macOS Recovery system.
- Option (⌥) or Alt: Start up to Startup Manager, which allows you to choose other available startup disks or volumes.
- Option (⌥)-Command (⌘)-P-R: Reset NVRAM or PRAM.
- Shift (⇧): Start up in safe mode.
- T: Start up in target disk mode.
The Mac is a 2014 Intel-based Mac. We use Command (⌘)-R to get into the built-in macOS Recovery system. In addition, we connected an external-drive to the Mac. We were able to:
- Select this external-drive as the target disk.
- Install MacOS on this external-drive.
- Reboot the Mac through this external-drive.
- Found the
/etc/synthetic.confin the internal disk andrm /etc/synthetic.conf.