When I kill emacs (with killall emacs from a shell prompt, for example), and I was editing a file, Emacs restarts with a message

filename has auto save data; consider M-x recover-this-file

If I had recently saved the file, then modified it and then undone the changes, so that it looks just like the saved version, this message is displayed, even though the auto-save file has no changes at all (seen via file size or M-x diff)

How can this be disabled?

I could not find something in either the official documentation, or emacswiki.

1 Answer 1


I don't think there is a built-in mechanism for this, so you may need to roll your own.

Don't have a direct answer, but I have something similar in my config: I don't want to be prompted for confirmation when killing a file that matches what is on disk. To check this I'm running diff and then scanning the output -- you can probably do something similar for your use case.

(defun my/matches-file-p ()
  "Return t if the current buffer is identical to its associated file."
  (autoload 'diff-no-select "diff")
  (when buffer-file-name
    (diff-no-select buffer-file-name (current-buffer) nil 'noasync)
    (with-current-buffer "*Diff*"
      (search-forward-regexp "^Diff finished \(no differences\)\." (point-max) 'noerror))))

(defun my/kill-buffer ()
  "Kill the current buffer.
Don't prompt for confirmation if the buffer is unmodified or matches its file."
  (when (my/matches-file-p)
    (set-buffer-modified-p nil))

Looking more at the auto-revert case. It looks like that prompt comes from after-find-file, which is looking at timestamps (file-newer-than-file-p). I don't see a straightforward way to customize or advise this behavior. Maybe you could advise after-find-file to compare the file with its auto-save file and set the warn argument to nil if things match.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.