Hello, In order for CFFI to load, I need to load jna-4.2.2.jar. Right now, I have to do something like this: (let ((jar-pathname #P"c:/Users/977315/.m2/repository/net/java/dev/jna/jna/4.2.2/jna-4.2.2.jar")) (java:add-to-classpath (namestring jar-pathname))) To automate loading of ASDFs that require CFFI I tried to automate the process by adding a before method to 'load-op: (eval-when (:compile-toplevel :execute :load-toplevel) (defmethod operate :before ((operation (eql 'asdf/lisp-action:load-op)) (component (eql :cffi))) (let ((jar-pathname #P"c:/Users/977315/.m2/repository/net/java/dev/jna/jna/4.2.2/jna-4.2.2.jar")) (java:add-to-classpath (namestring jar-pathname))))) That did not work. I did read the ASDF manual, but could not figure out how to do it. I suspect someone has figured out the right way. What is it? Thanks, Mirko