Yes I did restart. And by updating spacemacs itself do you mean doing a git pull in the .emacs.d directory? Because I did do that. I start the REPL and freezes but I can work around it by doing C-g. I see a message that says Error in process filter : Quit [2 times]. But now I can switch to the REPL buffer and it seems to work fine.

Did you update your .spacemacs file from the template, using SPC f e D

I assume it's been a while, so there may be some important changes to copy across from the Spacemacs template, especially if it's been a while since you updated Spacemacs.

I suggest trying the simplest Clojure or ClojureScript project, to check the issue is not caused by a library. Also try using the Emacs debug tools https://github.com/syl20bnr/spacemacs/wiki/Debugging#enable-debug

You could also comment out any layers you don't need, then adding them back one by one and see which breaks

Yea it was specific to a project. Some how tools.nrepl is being added as a dependency but I dont see it in the deps tree. So gotta look into more