I'd recommend staring emacs with nrepl-log-messages set to t When the freezing happens, send SIGUSR2 to the emacs process (this is a well-documented technique) to abort whatever it was doing. Share the *nrepl-log-<your repl name>* buffer contents afterwards It also could be anything else besides from cider e.g. clojure-mode, clojure-lsp if you use it

It also is wise to favor cider-connect over cider-jack-in workflows, so that Emacs can be killed and you can reconnect to the same repl which is useful for: • not losing your state • maybe, debugging your issue

I don't know the cider-connect workflow

https://docs.cider.mx/cider/basics/up_and_running.html#connect-to-a-running-nrepl-server The idea is to create a repl process from your terminal, then Emacs becomes sort of a thin client to it