Most Emacs users are probably aware of the current problem with using Gnu Privacy Guard (GnuPG) with Emacs. The TL;DR is that although you can open GnuPG encrypted files, you can’t edit and resave them. This problem was introduced in GnuPG 2.4.1 and is apparently hard to fix. As of this writing, it persists in all the GnuPG releases after 2.4.0.
A simple solution is to simply downgrade to GnuPG 2.4.0. It’s a simple solution, that is, unless you installed GnuPG with Homebrew. In that case, the solution is a bit more difficult but still not hard. I wrote about how to do it here. In a comment to that post, Michael Alan Dorman notes that another suggested—and far easier solution—is to simply add
(fset 'epg-wait-for-status 'ignore)
to your init.el. That seemed like an easy solution and I resolved to try it the next time I faced the problem.
I’ve just stumbled across a reddit post that suggests that solution will corrupt your encrypted files and make them unreadable. I haven’t had time to verify that yet but I wanted to get the warning out immediately. Hence the PSA. Until the issue is resolved, I’d avoid using that solution and downgrade to version 2.4.0 instead.