diff --git a/uiop/os.lisp b/uiop/os.lisp
index e2c6058f5df6b3c29e7c747fab9c2c5565b890c2..9d93138955b980941f10b526be2ad9af5bd87773 100644
--- a/uiop/os.lisp
+++ b/uiop/os.lisp
@@ -238,7 +238,7 @@ suitable for use as a directory name to segregate Lisp FASLs, C dynamic librarie
      #\_ #'(lambda (x) (find x " /:;&^\\|?<>(){}[]$#`'\""))
      (format nil "~(~a~@{~@[-~a~]~}~)"
              (or (implementation-type) (lisp-implementation-type))
-             (or (lisp-version-string) (lisp-implementation-version))
+             (lisp-version-string)
              (or (operating-system) (software-type))
              (or (architecture) (machine-type))))))