If you are using tmux plugin tmux-resurrect and you have upgraded tmux to version 3.0, you have probably noticed tmux server crashing while restoring sessions with error message [server exited unexpectedly]. Fortunately, the problem has been identified and a fix is coming. But until then, here is a workaround for macOS users.
Workaround
The best way to install software on macOS is to use brew. To downgrade to a previous version, there are 2 ways.
Install formulae with particular version
One way to install particular version of the software is to install it using brew install <name>@<version>. Sadly, formulae for older version of tmux doesn’t exist.
brew search tmux@2.9
No formula or cask found for "tmux@2.9".
Closed pull requests:
Tmux 3.0 (https://github.com/Homebrew/homebrew-core/pull/47241)
tmux 2.9 (https://github.com/Homebrew/homebrew-core/pull/39265)
Install from older revision of a formulae
To install tmux 2.9a, use the following steps:
brew uninstall tmux
brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/c8cff106b17b90472cc6e251b9e5c2daf4fd8d46/Formula/tmux.rb
tmux -V
tmux 2.9a
To prevent from upgrading (until this is fixed), pin the version:
brew pin tmux
To unpin and upgrade:
brew unpin tmux
brew upgrade tmux
