Cacher is the code snippet organizer for pro developers

ref: https://github.com/tmux/tmux/issues/543

I was experiencing the same issues post-upgrade, but finally got it working again this morning.

Here's what I did:

brew install reattach-to-user-namespace
Ensure the following is set in .tmux.conf:

set -g default-shell $SHELL 
set -g default-command "reattach-to-user-namespace -l ${SHELL}"
In .vimrc or ~/.config/nvim/init.vim (I use Neovim):

set clipboard=unnamed
Now all is well and I can copy/paste between system <-> vim sessions using vim keybindings and/or system ctrl+c / ctrl+p.