Updating from 2.0 to recent 4.0_BETA:

  You have created new directories. Run mtree to set permissions? (y/[n]) y
  mtree: unknown user `_rwhod'
  mtree: failed at line 1103 of the specification
  Do you want to rebuild the device nodes in /dev? (y/[n]) y
  Do you want to rebuild the password databases from the new master.passwd? (y/[n]) y

ISTM it'd make more sense to refresh the pwd.db first, _then_ try to
run mtree.

-- 
(let ((C call-with-current-continuation)) (apply (lambda (x y) (x y)) (map
((lambda (r) ((C C) (lambda (s) (r (lambda l (apply (s s) l))))))  (lambda
(f) (lambda (l) (if (null? l) C (lambda (k) (display (car l)) ((f (cdr l))
(C k)))))))    '((#\J #\d #\D #\v #\s) (#\e #\space #\a #\i #\newline)))))