1 files changed, 2 insertions, 1 deletions

diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
index e0e5237133b..341565bc52a 100644
--- a/lisp/mail/rmail.el
+++ b/lisp/mail/rmail.el
@@ -640,7 +640,8 @@ Note:    it means the file has no messages in it.\n\^_")))
     (unless (and coding-system
                  (coding-system-p coding-system))
       (setq coding-system (detect-coding-region from to t)))
-    (unless (eq coding-system 'undecided)
+    (unless (memq coding-system
+                  '(undecided undecided-unix))
       (decode-coding-region from to coding-system)
       (setq coding-system last-coding-system-used))
     (set-buffer-modified-p modifiedp)