Hello, If I enter `(read)' at the SLIME REPL, Emacs gives me the following messages: error in process filter: slime-mark-output-end: Wrong type argument: integer-or-marker-p, nil error in process filter: Wrong type argument: integer-or-marker-p, nil The offending change seems to be tcr's `C-c C-z' patch from 2008-08-14: merely selecting the REPL window is apparently not enough. After setting the current buffer to be the REPL buffer, READ works as expected. Ariel