The problems with BUNDLE-OP were triaged to problems in ABCL's use of :WILD-INFERIORS on directories referred to via symlinks. OS X symlinks /private/tmp to /tmp which was why the problem was mysteriously not working only on this platform. This error was fixed when I [finished re-working DIRECTORY to default to :RESOLVE-SYMLINKS as nil][r14624] which currently exists in abcl-1.3.0-dev. If you wish to conditionalize on the fix, the form (not (second (third (sys::arglist 'directory)))) should return T for versions of ABCL that work with BUNDLE-OP on OS X. We supposedly releasing ‘abcl-1.3.0’ real soon now, but this has been the case for several months, as time (and more bugs) kept cropping up. [r14624]: http://abcl.org/trac/changeset/14624 -- "A screaming comes across the sky. It has happened before but there is nothing to compare to it now."