Observe: ; SLIME 2008-02-10 STYLE-WARNING: redefining EMACS-INSPECT (#<BUILT-IN-CLASS FUNCTION>) in DEFMETHOD CL-USER> (require :swank) ... debugger invoked on a SIMPLE-TYPE-ERROR: *PACKAGE* can't be a deleted package: *PACKAGE* has been reset to #<PACKAGE "COMMON-LISP-USER">. Type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL. restarts (invokable by number or by possibly-abbreviated name): 0: [ABORT ] Return to SLIME's top level. 1: [CLOSE-CONNECTION] Close SLIME connection 2: Exit debugger, returning to top level. (SB-INT:SANE-PACKAGE) The quick and dirty fix is: --- swank-loader.lisp.orig 2008-02-14 10:56:14.078125000 -0600 +++ swank-loader.lisp 2008-02-14 10:56:30.828125000 -0600 @@ -19,7 +19,7 @@ ;; (load ".../swank-loader.lisp") (eval-when (:compile-toplevel :load-toplevel :execute) - (when (find-package :swank) + (when (and (find-package :swank) (not (asdf:find-system :swank))) (delete-package :swank) (delete-package :swank-io-package) (delete-package :swank-backend)))