Trying to upgrade my Pi-hole host from Raspbian Stretch to Buster, during the upgrade process, I detached the tmux session and left for a while, when I came back, I can’t create or attach my tmux session anymore, got error message as below:
pi@pi-hole ~ $ tmux a open terminal failed: missing or unsuitable terminal: xterm-256color pi@pi-hole ~ $ tmux open terminal failed: missing or unsuitable terminal: xterm-256color
This will make tmux work again.
Some instructions will tell you to kill the tmux server and start a new one:
This will lose the current session which is not preferred, especially during the system upgrade process.