Hi, ASDF developers I think asdf:*compile-file-failure-behaviour* should never been set to :error, just :warn is good. CLHS [1] said about COMPILE-FILE's 2nd and 3rd return values: "The secondary value, warnings-p, is false if no conditions of type error or warning were detected by the compiler, and true otherwise. "The tertiary value, failure-p, is false if no conditions of type error or warning (other than style-warning) were detected by the compiler, and true otherwise." This means, any warnings other than style-warning will cause COMPILE-FILE return T on its third return value. Than every Lisp file which contains a general (WARN "...") form, when compiling, will cause COMPILE-FILE return T on its third return value, and therefore was marked as "failure" (by ASDF). In current asdf.lisp, asdf:*compile-file-failure-behaviour* was defined as follow: (defvar *compile-file-failure-behaviour* (or #+sbcl :error #+clisp :ignore :warn) "How should ASDF react if it encounters a failure (per the ANSI spec of COMPILE-FILE) when compiling a file? Valid values are :error, :warn, and :ignore. Note that ASDF ALWAYS raises an error if it fails to create an output file when compiling.") I don't know why SBCL here is special, but this definition caused my project (cl-net-snmp 6.0) failed to be compiled by ASDF "only" on SBCL. Just try to put following lines in your ASDF based project and try to build it: (eval-when (:compile-toplevel) (warn "xxx")) you'll find how ludicrous the current setting of asdf:*compile-file-failure-behaviour* are. Regards, Chun Tian (binghe) [1] http://www.lispworks.com/documentation/HyperSpec/Body/f_cmp_fi.htm#compile-f...