I just ran into this issue myself!
Open your terminal, trying installing:
brew install htop
Output:
$ brew install htop Warning: It appears you have MacPorts or Fink installed. Software installed with other package managers causes known problems for Homebrew. If a formula fails to build, uninstall MacPorts/Fink and try again. Error: You must `brew link autoconf' before htop-osx can be installed
Now, fix:
sudo brew link autoconf
Let me know if this helps!
After, it might ask you to link "htop":
sudo brew link htop
Basically, all the "linkking" problems need root to create the correct symlinks in order to work properly on your system.
Regards,