# Threading broken in Apple Mail on the Mac and in iOS **URL:** \ **Category:** Product Support\ **Created:** [19.Июнь.2019 16:50:16 UTC](https://meta.discourse.org/t/threading-broken-in-apple-mail-on-the-mac-and-in-ios/120827 "2019-06-19T16:50:16Z")\ **Posts on this page:** 1\ **Showing post:** 1
**Author:** ![adamengst](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/adamengst/32/116607_2.png) [@adamengst](https://meta.discourse.org/u/adamengst)\ **Post date:** [19.Июнь.2019 16:50:16 UTC](https://meta.discourse.org/t/threading-broken-in-apple-mail-on-the-mac-and-in-ios/120827/1 "2019-06-19T16:50:16Z")
Some time ago there was a discussion of threading being broken in Apple Mail. > [@Mac Mail Threading](https://meta.discourse.org/t/mac-mail-threading/56194): > > Yes, sigh, I know, again. 1.7 breaks the workaround we had for Mac Mail threading, namely always including “Re:” at the start of the subject Setting for email subject Re: [%{site\_name}] %{optional\_pm}%{topic\_title} Unfortunately, Discourse 1.7 sensibly does not include an “In-Reply-To” on the first post, and this results in the first post being threaded separately from the replies in Mac Mail. I have a hack to put the “In-Reply-To” back: @message.header['Message-ID'] = incoming\_mes… One of my users just reported this as having changed on our site, since we switched recently from SendGrid to Amazon SES. > **[Discourse topic openers separate from replies](https://talk.tidbits.com/t/discourse-topic-openers-separate-from-replies/9031)** > > In both Mail.app and iOS Mail (latest versions), the first message in a topic (like a TidBITS article) and the replies to that topic are separate threads. Looking at the list messages I haven’t deleted, a topic started May 28 is a single thread... > [@On another topic](https://meta.discourse.org/t/9031/3): > > A topic-starting message from 5/31, when threading still worked contains this: > > ```plaintext > Message-ID: > > ``` > > While my message starting this topic has this: > > ```plaintext > Message-ID: <0100016b6b37a230-92ef9d2a-ded7-43f2-b9a8-e5b9e574cf2e-000000@email.amazonses.com> > > ``` > > which doesn’t match the Message-ID references found in these headers in your reply: > > ```plaintext > In-Reply-To: > References: > > ``` > > My guess this is the problem. I think all the replies remain threaded because they all contain matching References. Topic-starting messages don’t contain a References header. If Amazon SES can avoid replacing Message-IDs or if Discourse can include a self-referential References header in topic-starting messages, the problem could go away. > > I think this is a problem in Mail because it tries to be an old-school (proper) mail agent, using headers like this for threading, while Gmail is “dumb” and just uses the Subject. It would seem that the problem is related to the Message-ID header being different. It doesn’t seem that it’s possible to override Message-ID on SES: > **[Amazon SES header fields - Amazon Simple Email Service](https://docs.aws.amazon.com/ses/latest/dg/header-fields.html)** > > Describes the header fields that Amazon SES accepts. > - Message-ID ( **Note:** Amazon SES overrides any Message-ID header you provide.) Any other thoughts about how I might be able to get threading to work for my users relying on Apple Mail (which is most of them)? @peternlewis. are you still having issues here? What email service are you sending through? --- _[View the full topic](https://meta.discourse.org/t/threading-broken-in-apple-mail-on-the-mac-and-in-ios/120827)._