I recently upgraded to macOS Catalina and ever since my tmux seems to be broken. Whenever I run a tmux command or even just type tmux I get the error: [exited] ^[[?1;2c. I have reinstalled tmux multiple times with homebrew, I have restarted my computer, I have deleted everything from my .tmux.conf file, and I tried installing reattach-to-user-namespace just in case which seemed to be the problem for some other people but none of this has made any impact. I am using a zsh terminal and tmux used to work fine with it up until recently (no changes were made other than updating OS).

  • What is the default shell listed in your .tmux.conf file?
    – DrZoo
    Oct 15, 2019 at 19:53
  • @DrZoo I set it to zsh
    – mlz7
    Oct 15, 2019 at 20:42
  • and yes I sourced the config after every change
    – mlz7
    Oct 15, 2019 at 20:43
  • I'm also facing this problem. Did you find a solution?
    – Leo-T
    Oct 20, 2019 at 4:19
  • 1
    @Leo-T I was able to resolve it by uninstalling, restarting, installing, etc. a couple of times -- not sure what exactly the problem was but I think it has something to do with not cleaning up the prior installations
    – mlz7
    Oct 24, 2019 at 20:41

3 Answers 3


I encountered same problem for byobu.
I tried

pkill byobu..

not resolved...
Then I tried

pkill tmux 

and it solved the problem for me...
The problem might've been due to tmux upgrade which was earlier this morning...
tmux 3.1a -> 3.1b

Also check this link to another related answer.


Ok so since posting this question, my problem seems to have resolved itself. I have not changed anything with regards to my tmux installation directly so I am not 100% sure what exactly caused this issue or how it was resolved (apart from maybe restarting a couple more times?). I am posting this for future reference but if anyone is able to figure out why this problem was happening, I will gladly accept their answer instead.


Kill the old tmux processes, and then reinstall again.

ps -ef |grep tmux
  • 1
    rifaqat already suggested pkill tmux, and the OP reported that the problem went away after reinstallation, so you don’t seem to be suggesting anything new here.
    – Scott
    Aug 24, 2020 at 6:35

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