1 files changed, 5 insertions, 0 deletions

diff --git a/lisp/mail/rmailout.el b/lisp/mail/rmailout.el
index 8e4db51b5ea..90aedd8f62a 100644
--- a/lisp/mail/rmailout.el
+++ b/lisp/mail/rmailout.el
@@ -122,6 +122,11 @@ starting with the current one.  Deleted messages are skipped and don't count."
                         ;; If MSG is non-nil, buffer is in RMAIL mode.
                         (if msg
                             (progn
+                              ;; Turn on auto save mode, if it's off in this
+                              ;; buffer but enabled by default.
+                              (and (not buffer-auto-save-file-name)
+                                   auto-save-default
+                                   (auto-save-mode t))
                               (rmail-maybe-set-message-counters)
                               (widen)
                               (narrow-to-region (point-max) (point-max))