Recovery Mode is the special salvation of the Mac that first launched with OS X 10.7 Lion. How to install a new copy of macOS Big Sur in Recovery Mode If you are using a laptop, make sure it is connected to a power source.An Internet connection is needed in order to reinstall the macOS operating system. Make sure the computer on which you're installing a fresh copy of macOS Big Sur can be connected to the internet, either via Wi-Fi or Ethernet. You can also back up files and documents using a cloud-based storage system like Dropbox, OneDrive, or the easiest: iCloud. It is a good idea to perform one full backup before starting with a clean copy of macOS Big Sur. Completing this process replaces the core files of macOS Big Sur in case something wasn't working right before. Applications and settings will remain the same. Reinstalling a fresh copy of macOS Big Sur will not affect your current settings. If something doesn't quite work right after you've installed macOS Big Sur, you can reinstall the operating system so it is a fresh copy.
