After running brew upgrade node to upgrade my Node.js installation on macOS, Homebrew decided to run brew cleanup automatically.
It was doing its things, with a bunch of Removing: /Users/..... until I got the error
Error: Permission denied @ apply2files - /usr/local/lib/docker/cli-plugins
🤔
See "docker" in the path?
Turns out I had deleted Docker recently and this was causing an error. What I did to fix was to recreate a folder of the Docker app:
mkdir -p /Applications/Docker.app/Contents/Resources/cli-plugins
and running
brew cleanup
Again. The issue was fixed.
Your issue might be caused by another library missing, not Docker, so in this case you can Google the specific error message you have and see if someone else had the same issue and figured it out. But that's a start.