How can I prevent mail attachments embedding when sending mail

I remind everyone that I have long experience investigating this issue. I have done so with every version of Mail and OSX. There is no doubt that a message with image files and HTML will often be problematic to recipients using Outlook and Outlook Express. The problem is not really Apple's but in Lion they have tried to do something new about it. I disagree, however, with what they have done. In past versions of OSX and Mail you could manage the problem via the use of the Format/Make Plain Text command -- but that generally fails in Lion and Mail 5.x.

In direct communication with Apple staff, after submitting this this as a Bug, I was informed that the behavior I reported is as expected/designed. They further stated that a change was made to so that Mail should encode plain text messages that have inline image attachments as HTML -- thus an acknowledgement that RTF produces HTML. They said the motivation for this change is to work around a long standing problem with Microsoft Exchange Server parsing of multipart mixed MIME messages, wherein that server might change content disposition and cause apparent data loss.

Prompted by an experience with one of three test messages Jürgen sent, I devised a test. In Lion, in Aperture (could just have easily been iPhoto) I chose some images, and clicked to have it compose a new message in Mail. Then in the New Message, I added an empty text file as the final attachment. Then I used the command, Format/Make Plain Text. As in all previous tests, the draft message was changed to look like Plain Text. But unlike all other such tests, when sent, the resulting message remained in Plain Text (which I define as being without HTML.) For control purposes I did the same test again, but without the added empty text file attachment -- as in all other such tests, the result when sent was a message with HTML content, despite having selected to make Plain Text.

So there is something very odd when the outcome of Format/Make Plain Text and subsequent sending can be different depending upon the presence of a trailing empty text file (worked equally well to use a text file containing only Plain Text created in Text Edit). These tests all involved the same SMTP, so that would seem to not be a factor. I am thinking how best to communicate this to proper Apple staff, probably as a follow up to my earlier Bug Report.

Ernie

Ernie,

I'm truly impressed with your perseverance. This method does indeed work as described. You must have been a computer hacker in another life. I don't know if you should tell Apple about this. They could consider it a bug to be fixed.

Hi Ernie, hi etresoft,

thx for your research, Ernie! I am not familiar enough with apples policies in such circumstances to give any advice in contacting (or better not contacting, see etresofts point :-) ) apple folks. I can only state, and please feel free to use this as an argument for whatever communication with them, that there are at least 12 freelancers (who contacted me, 10 photographers and 2 illustrators) like myself in Germany who are very annoyed by this behaviour of mail. All of them are severely handicapped in one of most important tasks, which is selling and distributing their work to customers. And all their customers are too "big" to change their mail-architecture. One of those fellow-sufferers has already re-installed a windows-machine just for sending his mail, three others are seriously thinking about that.

To my mind, if apple really did this "on purpose", the only thing needed would be a simple check-box in the preferences or every mail-edit window, that, when checked, returns to the "old" send paradigma.

By the way, choosing different SMTP does indeed only work sometimes (and sometimes not). Up to now, adding a TXT is still my only remedy for sending JPG to the majority of publishers.

cheers, Jürgen

Thanks for reminding me about your sample survey. It may prove useful -- if so, I will send you a suggestion about a useful new topic post you could make about that survey, so that I could reference it in other communications.

I have to both leave Lion for most of the weekend and for a time the computer, but I have just made a quick test of adding a Signature, and placing the .txt file in it. It will accomplish the same benefit as separately attaching as the final file.

A complication to using the Signature when composing the message from within Aperture (or iPhoto, or Graphic Converter, or likely any app so equipped) is that that Composition may ignore the Signature select for the account, but it can quickly be re-selected. It has been a mystery to me for a long time as to why the composition of a New Message from within one of these apps will ignore the Mail Preference to use Plain Text, and compose the message in RTF -- but it does. Thus the long practice to use the command to Make Plain Text (or rely upon the prior default at sending to convert the RTF to Plain Text if only one font was being used.) But reliance upon the command to Make Plain Text is what will not work as expected in Lion and Mail 5.x!

I suspect the Signature method will be simpler if composing the message from within Mail.

All the best,

Ernie

Further thoughts about why this text attachment works.

Rereading what was communicated to me about the change to send in HTML, I believe that Mail is checking for following text after any attachment with Inline disposition, and if none, the final attachment. This .txt file does not have an Inline disposition in its header. The test, if triggered sends in HTML even if the message has been converted to Plain Text. Thus this final attachment lets Mail ignore the concern about needing to send in HTML.

Ernie

Ernie,

I don't believe the problem is anything to do with HTML - even when sending an HTML format mail, one should be able to include an attached image which is NOT inline, but rather simply an attached file. In fact, it should be possible to do both within the same mail, ie. have an in-line image, such as a signature logo, within the message while also attaching an image file for the recipient to save to disk.

I am still convinced that the problem is simply that Apple Mail always flags attached images with content-disposition type 'inline' rather than 'attachment'. If Apple were to implement correctly the content-disposition header (as per IETF RFC 2183) then there would be no issue and we would be able to send attachments either in-line or as attached files regardless of whether the message is plain text or HTML.

C.

I do not share your opinion about any conflict with IETF RFC 2183 -- clearly Inline is a valid option.

Factors you appear to not be considering include:

The web mail interface for say Gmail, sees the files sent via Mail as having attachments, and they are in good order.

Other web interfaces, such as as those for major ISP provided email accounts likewise recognize that the files are attached, and in good order.

Sending to those email clients such as Outlook in Plain Text willl not present any problems with availability of the files as attachments.

Sending to, say, another email client such as Thunderbird likewise will see the files presented as attachments.

Files sent attached to messages from Windows users with Thunderbird can likewise exhibit a disposition of Inline, as can messages sent via YahooMailer.

Ernie

Jürgen from OHZ wrote:

To my mind, if apple really did this "on purpose", the only thing needed would be a simple check-box in the preferences or every mail-edit window, that, when checked, returns to the "old" send paradigma.

But that isn't simple, that is another layer of complexity. It would double the number of formats that Apple would then have to support.

You are acting as if Apple Mail can't send attachments at all. Users need to install Windows if they want to send e-mail messages? Come on!

Here is the truth: Messages composed in Apple Mail in Lion will appear on the recipient's machine the same way that they appear on the sender's machine, regardless of what e-mail client they have. Call me crazy, but I call that a feature, not a bug. If you need more fine-grained control over your e-mail than that, then install some 3rd party software. You can use anything from Attachment Tamer to Outlook 2011. You do not need Windows.

clearly Inline is a valid option

Indeed this is a valid option - just the wrong option for an attachment that is NOT intended to be in-line!

Factors you appear to not be considering include:

The web mail interface for say Gmail, sees the files sent via Mail as having attachments, and they are in good order.

Other web interfaces, such as as those for major ISP provided email accounts likewise recognize that the files are attached, and in good order.

Sending to those email clients such as Outlook in Plain Text willl not present any problems with availability of the files as attachments.

Sending to, say, another email client such as Thunderbird likewise will see the files presented as attachments.

Files sent attached to messages from Windows users with Thunderbird can likewise exhibit a disposition of Inline, as can messages sent via YahooMailer.

Full credit to all these email apps that appear to be able correctly to present attachments sent from Apple Mail. This does not necesarilly mean, however, that the messages being sent by Apple Mail are correct; there are plenty examples of web browsers being able correctly to display web pages even when those pages have been incorrectly coded...

C.

The Content Disposition has nothing to do with whether the file is an attachment, but only with some apps how it is to be presented. It is the disposition of the Content and not of the file.

Most modern email clients have been updated to view image files in place regardless of whether Inline disposition is used or not.

Presence of HTML is the reason that Outlook messes up, however. But if Inline were not used, it might do better -- that is why the developer of Mail Tamer gets some business, even though it should not be needed.

Ernie

C.

You might also be interested in an exchange with Adam Nohejl, the developer of Attachment Tamer found at:

https://discussions.apple.com/thread/2732735?start=30&tstart=0

All the best,

Ernie

Ceres1 wrote:

Full credit to all these email apps that appear to be able correctly to present attachments sent from Apple Mail. This does not necesarilly mean, however, that the messages being sent by Apple Mail are correct; there are plenty examples of web browsers being able correctly to display web pages even when those pages have been incorrectly coded...

And there are plenty of examples of web browsers being unable to correctly display web pages even when those pages have been correctly coded. What to take a guess at who might have written those browsers? 🙂

I can guarantee that the e-mail messages that Apple Mail generates are correct according to all accepted standards and conventions. That fact is indisputable and provable.

The problem is that Apple doesn't care much for backwards compatibility. Just as the don't care much about Flash, they don't care much about Outlook 2007. They have come up with a method that allows Lion Mail messages to appear as close as possible to how the sender meant them to appear. To do this, they sacrificed some of the advanced capabiltiies like controlling internal formats and attachment methods.

Things are getting better. As far as I know, the current versions of Outlook do not have these bugs and handle Apple Mail messages with no problems. I know that Lotus of all things handles them just fine. Current versions of Internet Explorer now correctly display web sites. When it comes to supporting modern browsers, I need more hacks for current versions of Firefox than current versions of Internet Explorer.

I am having the same problem everyone else is reporting, sending from Mail.app and receiving with Gmail. Outlook and Microsoft Windows are not involved at all. Here are the steps to reproduce the problem:

1. Create email in Mail on OS X Lion.

2. Attach a jpg or gif file.

3. Send the mail to a Gmail account.

4. Open Gmail in Safari on Mac.

5. Open email.

Result: Image is displayed inline, and not attached.

At no time were Microsoft products involved in this test at all.

Thanks for reporting this. You have found a similarity of behavior, and one which is still dependent upon the presence of HTML or not, and altered by a text file attachment as with the earlier discussions.. If you send with the empty text file attachments, they are reported as attachments, despite continuing to have a Content Disposiont of Inline.

In either case they are attachments can be downloaded with their true file name. This is different than the behavior in Outlook, with HTML, in my experience.

Ernie

Christopher Shaffer wrote:

Result: Image is displayed inline, and not attached.

Yes. This is the way it is designed to work. It doesn't matter if you use Outlook or a web browser to view the e-mail message. The image is displayed inline because that is how Apple Mail defines it.