Fix Error - Another active Homebrew update process is already in progress

Error: Another active Homebrew update process is already in progress.
Please wait for it to finish or terminate it to continue.
Failed during: /opt/homebrew/bin/brew update --force --quiet

Do a ps -ef and see what all brew processes are running,

ps -ef | grep brew
  501  3564  2176   0  1:43PM ttys000    0:00.03 /bin/bash /opt/homebrew/Library/Homebrew/brew.sh update
  501  3785  3564   0  1:43PM ttys000    0:00.00 /bin/bash /opt/homebrew/Library/Homebrew/brew.sh update
  501  3818  3817   0  1:43PM ttys000    0:00.01 /Library/Developer/CommandLineTools/usr/libexec/git-core/git remote-https origin https://github.com/Homebrew/homebrew-core
  501  3820  3818   0  1:43PM ttys000    0:00.12 /Library/Developer/CommandLineTools/usr/libexec/git-core/git-remote-https origin https://github.com/Homebrew/homebrew-core
  501  5728  2176   0  2:04PM ttys000    0:00.01 grep brew

% kill -9 3564
[1]  + killed     brew update

% kill -9 3785
[1]  + killed     brew update