Hi Masaya, list! I use batch file which deletes all fasl files to do complete cleanup. If I wanted to force recompilation of a particular system, I would just "touch" all files. See also https://en.wikibooks.org/wiki/Common_Lisp/External_libraries/ASDF/Budden's_infrequently_asked_questions - it describes a way to find fasls of the system.