Hi,

We have Exchange 2013 and Outlook 2010 clients. Recently, a email arrived with various PDF and Doc attachments inserted throughout the body of the message. 

When we received the email and viewed it in Outlook, the message appeared to cut off half way through. The remaining text was found in the numerous ATT0001.htm attachments. According to the title window, the message was in HTML format.

When viewing the same email on iPhone, the message displays correctly - all text is present and the attachments appear in-line, just as the sender intended.

The message headers include

Content-Type: multipart/alternative;
boundary="Apple-Mail=_EC258E9B-097C-4F7B-97F1-D997E5A6D497"

This KB describes similar results, but has not been updated to include whether Exch 2013 is also affected.

Is there anything I can do on our Exchange 2013 server to convert or preserve the message as it was intended?

Kind regards

Hi,

Does this message sent from App Mail?

Generally, this happens because Microsoft Exchange Server is reformatting messages sent through it.

The Exchange server insists that message text must always be first and attachments must always be last. As soon as the Exchange software sees one attachment in a message, it stops looking for text, and treats anything else in that message as an attachment. Any remaining text sections are converted into attachment sections, and given fake file names (like "ATT00001.htm").

At this time, there is no way to make the Exchange server stop turning text sections into attachment sections. The only workaround is to include attachments at the end of a message, after text and after any signatures.

Workaround

• In Apple Mail, go to the menu Edit > Attachments

1. Make sure the following settings are checked:
   Always Send Windows-Friendly Attachments
   Always Insert Attachments at End of Message

• Use the menu Mail > Preferences and go to the Composing section
• Make sure that Message Format is set to "Plain Text"

With these settings, any attachments added with the "Attach" paperclip button will be put at the end of your message, after all message text.

Best Regards.

Thanks. I understand the problem - it is mentioned in the KB article I linked above. 

What I'm amazed about is Microsoft was aware of the issue in Exchange 2007 but neglected to address it in either Exchange 2010 or 2013, or any of the updates and patches issued along the way.

It is somewhat embarrassing for Microsoft that an iPhone can render these messages as intended, yet Outlook on Exchange cannot. Microsoft have done well to make OWA on Exchange 2013 browser agnostic (something I am sure they did to appease the Safari/Mac users). It is a shame they did not continue this approach through to the way they handle emails from Apple Mail users.

According to this blog post Microsoft have discussions with Apple about making their mail accepted and supported, so it seems this issue gets overlooked.

• Marked as answer by Andrew S. James 22 hours 52 minutes ago