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

brew uninstall --force tmux
brew install tmux

fixed it for me.

Mine had the same problem.

$ tmux
dyld: Library not loaded: /usr/local/lib/libevent-2.0.5.dylib
Referenced from: /usr/local/Cellar/tmux/1.9a/bin/tmux
Reason: image not found
Trace/BPT trap: 5

Tried to install libevent but it was already there, not linked yet:

$ brew install libevent
Warning: libevent-2.0.21 already installed
$ brew link libevent
Warning: Already linked: /usr/local/Cellar/libevent/2.0.21
To relink: brew unlink libevent && brew link libevent

I solved it by doing exactly what was suggested above:

$ brew unlink libevent && brew link libevent
Unlinking /usr/local/Cellar/libevent/2.0.21... 4 links removed
Linking /usr/local/Cellar/libevent/2.0.21... 25 symlinks created
$ tmux -V
tmux 1.9a

I have the same issue with tmuxinator, And get that error in my case I upgraded tmux with:

brew upgrade tmux