I can't reproduce your issue. sbcl --eval '(require :asdf)' --eval '(trace compile-file load asdf::perform sb-ext:run-program)' --eval '(require :sb-posix)' sbcl --eval '(require :asdf)' --eval '(trace compile-file load asdf::perform sb-ext:run-program)' --eval '(asdf:load-system :sb-posix)' Both work fine for me. What ASDF configuration do you use? Could it be that you're running from a dumped image and that you're not exporting SBCL_HOME to a proper value? ASDF does something magic with SBCL_HOME for those output files. But yeah, I shall submit a patch to SB-GROVEL so that things should work even in screwy cases like that. Note that you don't need to define a ASDF-LOAD function now that ASDF has ASDF:LOAD-SYSTEM. [ François-René ÐVB Rideau | Reflection&Cybernethics | http://fare.tunes.org ]