Taking a stab, but you're not using Vim under tmux on a Mac, are you? If so, you need to do a tweak to get clipboard access. https://robots.thoughtbot.com/how-

Taking a stab, but you're not using Vim under tmux on a Mac, are you? If so, you need to do a tweak to get clipboard access. https://robots.thoughtbot.com/how-to-copy-and-paste-with-tmux-on-mac-os-x https://robots.thoughtbot.com/how-to-copy-and-paste-with-tmu... Otherwise the "+y / "+p commands should yank and paste system clipboard correctly.