I recently got this error while using Homebrew to install a package on macOS, in my case
➜ brew install rbenv ... Error: Your CLT does not support macOS 11. It is either outdated or was modified. Please update your CLT or delete it if no updates are available. Update them from Software Update in System Preferences or run: softwareupdate --all --install --force If that doesn't show you an update run: sudo rm -rf /Library/Developer/CommandLineTools sudo xcode-select --install Alternatively, manually download them from: ~https://developer.apple.com/download/more/~. Error: An exception occurred within a child process: SystemExit: exit
softwareupdate --all --install --force as suggested in the message didn’t help, so I ran
sudo rm -rf /Library/Developer/ and then
sudo xcode-select --install:
After doing this,
brew install rbenv worked fine.