Installing tmux but getting "dyld: Library not loaded Referenced from: /usr/"

I try to do brew install tmux it installs, but, probably due to previous failed and not fully removed non-brew attempts to install both it and libevent, when try to use tmux I get $ tmux dyld: Library not loaded: /usr/local/lib/libevent-2.0.5.dylib Referenced from: /usr/local/bin/tmux Reason: image not found Trace/BPT trap: 5 I tried to install libevent but I got: $ brew install libevent Warning: libevent-2.0.21 already installed, it's just not linked so I tried $ brew link libevent but I got Linking /usr/local/Cellar/libevent/2.0.21... Warning: Could not link libevent. Unlinking... Error: Could not symlink file: /usr/local/Cellar/libevent/2.0.21/include/event2/util.h Target /usr/local/include/event2/util.h already exists. You may need to delete it. To force the link and overwrite all other conflicting files, do: brew link --overwrite formula_name To list all files that would be deleted: brew link --overwrite --dry-run formula_name so I tried $ brew link --overwrite libevent but I got Linking /usr/local/Cellar/libevent/2.0.21... Warning: Could not link libevent. Unlinking... Error: Permission denied - /usr/local/include/event2/util.h so I tried $ sudo brew link --overwrite libevent Password: but I got Error: Cowardly refusing to sudo brew link You can use brew with sudo, but only if the brew executable is owned by root. However, this is both not recommended and completely unsupported so do so at your own risk. I'm stuck.