I seem to remember that I used to be able to press RET on a PDF attachment button in a Gnus article and have it open with pdf-tools. It's not working now, when I press RET I get prompted to save the PDF somewhere (after which I can use find-file to view it with pdf-tools). The prompt says "Save MIME part to:", just like when pressing o on the button (which runs gnus-mime-save-part). The same thing happens with E (gnus-mime-view-part-internally), which I also wouldn't expect.

Using either c or K c (the oddly named gnus-mime-copy-part and gnus-copy-article-part) does open the PDF attachment in a new buffer using pdf-tools, so a simple workaround would be to just use c instead of RET or E. But I really seem to remember that RET used to work (but I don't remember when it worked: I stopped using Gnus for a while, I'm probably not on the same versions of Emacs, Gnus and pdf-tools) and I don't know what changed.

Am I misremembering? Did this work at some point? How can I fix it?

I'm using Emacs 28.0.50, Gnus 5.13 and pdf-tools-20200214 from MELPA.

  • Omar, take a look at my edited reply below. Thanks.
    – aadcg
    Commented Nov 10, 2020 at 7:24

2 Answers 2


I just tested this on my setup and everything works the way you remember. I pressed RET on a pdf attachment from gnus (which runs gnus-article-press-button) and it got opened in a pdf-tools buffer.

I'm on GNU Emacs 26.3, Gnus 5.13 and pdf-tools 0.90 - all of them provided by the Guix package manager.

Let me share with you my pdf-tools config (in case that can be of any help).

(use-package pdf-tools
  :when window-system
  :custom (pdf-view-midnight-colors '("#ffffff" . "#000000"))
  ;; (setq image-scaling-factor 1) ; Emacs 27 needs this
  ;; this is a hack so that I can use docview links in org-mode
  (defalias 'doc-view-goto-page 'pdf-view-goto-page)
  :mode ("\\.pdf\\'" . pdf-view-mode)
  ((pdf-view-mode-hook . pdf-view-fit-height-to-window)
   (pdf-view-mode-hook . pdf-links-minor-mode)
   (pdf-view-mode-hook . pdf-annot-minor-mode)
   (pdf-view-mode-hook . pdf-view-auto-slice-minor-mode)
   (pdf-view-mode-hook . (lambda ()
                           (when (eq
                                  (frame-parameter nil 'background-mode)

Edit: I'm on GNU Emacs 27.1 and I'm facing the same issue that you describe. I tried to have a look at the git repository to try to understand what happened but I couldn't figure out. Anyway you can find a possible solution below:

(use-package gnus-art
  :commands gnus-mime-button-map
  :bind (:map gnus-mime-button-map
              ("RET" . gnus-mime-copy-part)))
  • Thanks for the edit. I don't think I need it anymore since I've grown accustomed to the default binding of c for gnus-mime-copy-part.
    – Omar
    Commented Nov 11, 2020 at 3:32

See https://github.com/redguardtoo/mastering-emacs-in-one-year-guide/blob/master/gnus-guide-en.org#open-attachment

Quoted from article,

Move focus over the attachment and press Enter or M-x gnus-article-press-button.

The variable mailcap-mime-data defines the program to open the attachment.

You can tweak the variable on Windows or macOS.

On Linux, run M-x mailcap-parse-mailcaps to load data from ~/.mailcap into mailcap-mime-data instead of modifying mailcap-mime-data directly.
  • Are you suggesting I add a line to ~/.mailcap using emacsclient to open PDFs? That sounds like it would work but I'm pretty sure I didn't do that before.
    – Omar
    Commented Apr 2, 2020 at 7:16
  • mailcap-parse-mailcaps can parse ~/.mailcap so Emacs Gnus knows which application should run when opening attachment.
    – chen bin
    Commented Apr 2, 2020 at 7:37

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