The PATHNAME serialization and ANSI-compatible namestrings issues should be solved as of [svn r12810][1]. 1. A PATHNAME with no namestring now has a non-printable representation (i.e. "#<PATHNAME (no namestring) …"). 2. The old, non-ANSI compatible #P(:host "host" :device nil …) output has been removed. 3. A PATHNAME namestring only contains '/' characters as directory separators. Any '\' passed in are converted. 4. UNC pathnames can be constructed via '\\server\mount\path' but have a non-printable namestring representations. Hopefully this puts these issues to rest. Any other outstanding problems related to this issues should be reported as bugs. [1]: http://trac.common-lisp.net/armedbear/changeset/12810 -- "A screaming comes across the sky. It has happened before, but there is nothing to compare to it now."