Did you install SLIME from ELPA? I believe that the version in ELPA is old and works best for Clojure. For Common Lisp, you probably want to get the latest SLIME from CVS. I ran into this problem last month.

If you don't want to use Clojure at all, you can just uninstall SLIME from ELPA, and get the latest SLIME with CVS:

 cvs -d :pserver:anonymous:[email protected]:/project/slime/cvsroot co slime-cvs

If you don't have it, I think you'll need to install CVS from Macports, Homebrew or something else, as OS X doesn't come with it installed. Put the directory `slime-cvs` somewhere like your `.emacs.d`.

Then configure SLIME and your Common Lisp implementation in your `.emacs` or your customization file for the starter-kit:

 (setq inferior-lisp-program "/usr/local/bin/sbcl") ; your Common Lisp impl
 (add-to-list 'load-path "~/.emacs.d/slime-cvs/") ; your SLIME from CVS directory
 (require 'slime)
 (slime-setup '(slime-repl))

You can then do `M-x slime` and this will start the CVS version of SLIME.

If you want to use both Common Lisp and Clojure with SLIME, and don't want to go fiddling around in your `.emacs` every time you want to try something in a different language, set up two distinct versions of SLIME: the old one from ELPA and the newest one from CVS. I wrote two functions which set up SLIME and either connect to Common Lisp or Clojure. To change languages, you still have to restart Emacs, but you don't have to mess with dotfiles to switch from one language to another. It's a bit hackish but it sort of works. Let me know if someone has a better way!

Hopefully it's obvious what the Emacs Lisp below does:

 (defun slime-common-lisp ()
 (interactive)
 (setq inferior-lisp-program "/usr/local/bin/sbcl") ; your Common Lisp impl
 (add-to-list 'load-path "~/.emacs.d/slime-cvs/") ; your SLIME from CVS directory
 (require 'slime)
 (slime-setup '(slime-repl))
 (slime))

 (defun slime-clojure ()
 (interactive)
 (add-to-list 'load-path "~/.emacs.d/elpa/slime-20100404/")
 (require 'slime)
 (slime-setup '(slime-repl))
 (slime-connect "localhost" 4005))

For Clojure you'd have to start the Clojure runtime and `swank-clojure` on port 4005, I think using Leiningen is the approved method:

Create a new project:

 $ lein new project
 $ cd project

In `project.clj`:

 (defproject newclj "1.0.0-SNAPSHOT"
 :description "FIXME: write"
 :dependencies [[org.clojure/clojure "1.2.0"]
 [org.clojure/clojure-contrib "1.2.0"]]
 :dev-dependencies [[swank-clojure "1.2.1"]])

Then:

 $ lein deps
 $ lein swank

References:

http://stackoverflow.com/questions/4419544/emacs-setup-for-both-clojure-and-common-lisp-with-slime-fancy-slime-autodoc/4420619#4420619

https://github.com/technomancy/swank-clojure/issues/closed#issue/31/comment/544166