Hi, I can't reproduce this issue. I tried --8<---------------cut here---------------start------------->8--- guix shell sbcl sbcl-uuid --pure -- sbcl --eval '(require :asdf)' --eval '(asdf:load-system :uuid)' guix shell sbcl sbcl-cl-containers --pure -- sbcl --eval '(require :asdf)' --eval '(asdf:load-system :cl-containers)' --8<---------------cut here---------------end--------------->8--- and both commands worked without any error. With each of the following commands, do you see the "uuid.fasl" file at the end or not? --8<---------------cut here---------------start------------->8--- ls -l $(guix build sbcl-uuid)/lib/common-lisp/sbcl/uuid/ ls -l $(guix build --check --no-grafts sbcl-uuid)/lib/common-lisp/sbcl/uuid/ --8<---------------cut here---------------end--------------->8---