diff --git a/README.org b/README.org
index 715195e..9c0698a 100644
--- a/README.org
+++ b/README.org
@@ -223,6 +223,8 @@ recommendation of [[info:emacs#Saving Customizations][saving customizations (inf
  column-number-mode t
  cursor-type 'box
  custom-file (locate-user-emacs-file "custom.el")
+ ;; Known problem: EasyPG fails to save files encrypted with GnuPG v2.4.1.
+ ;; Darwin: brew install gnupg@2.2
  epg-pinentry-mode 'loopback
  global-hl-line-mode t
  global-hl-line-sticky-flag t