Hi! This is with the current CVS SLIME (update a couple of minutes ago), GNU Emacs 21.3.50 from CVS (about a month ago), CMUCL 18e, and the current (0.7.7) CL-PPCRE on Linux x86. I can reproduce the problem like this: 1. Remove all FASL file (*.x86f) related to CL-PPCRE. 2. From a fresh Emacs start SLIME and then load the system CL-PPCRE. 3. CL-PPCRE is compiled but the REPL prompt never comes back. Instead, Emacs starts to use 99% of the CPU and is completely unresponsive, I have to kill it with xkill. I can compile CL-PPCRE from the command line without problems. Furthermore, this doesn't happen if CL-PPCRE is already compiled and has just to be loaded. I suspect this happens while SLIME tries to interpret CMUCL's compiler notes but I currently have no idea how to debug this. Cheers, Edi.