Hi, There is some problem with buffer cleanup when lisp connection is broken. Here's a minimal example. 1. Run your lisp remotely and start swank server 2. Connect w/ Emacs 3. Run remotely: pkill -9 <your favorite lisp> # the lisp dies 'orrible death 4. Restart lisp 5. Reconnect w/ Emacs Following messages get logged when you try to clean buffer (C-c M-o): error in process filter: slime-dispatch-event: Invalid rpc: Thread not found: :REPL-THREAD error in process filter: Invalid rpc: Thread not found: :REPL-THREAD error in process filter: slime-dispatch-event: Invalid rpc: Thread not found: :REPL-THREAD error in process filter: Invalid rpc: Thread not found: :REPL-THREAD Connected. Lemonodor-fame is but a hack away! error in process filter: slime-dispatch-event: Invalid protocol message error in process filter: Invalid protocol message And a slime error too: Invalid protocol message: Symbol "CLEAR-REPL-RESULTS" not found in the SWANK package. [file position = 37] "(:emacs-rex (swank:clear-repl-results) \"USER\" :repl-thread 7) " Thanks!, /S