Last Saturday I installed Update Rollup v3-2 for our Exchange 2007 SP3 server. I now have users receiving emails from our customers with PDF attachments that will not display in Outlook but will display okay in OWA. Checking the headers of the emails in question shows that they come from an Apple Mac environment. If the customer ZIPs the file and sends that instead of the PDF, it comes through and displays alright. Anyone have any suggestions?

I am re-posting this from the Microsoft Exchange Team blog; it was posted a few weeks ago: -------------- start quote Blended Messages Starting with Exchange 2007 service pack 3 roll up 3 (E12SP3RU3) and Exchange 2010 service pack 1 rollup 4 (E14SP1RU4) are a set of changes to how Exchange handles /mixed body messages. We think that in general your users will enjoy the less mangled nature of these messages, but if I’ve learned anything from fourteen years of working on Exchange, it’s that “different == angry”. People get used to our behavior, so even when it’s wrong (or incomplete) they expect the same behavior, and come to rely on it. Consider this is your fair warning that this change is coming, some details on how it works, where it works, and where it doesn’t. We're adding support for Exchange to combine multiple body parts into a single, aggregate body. The short of this is that broken up messages should show combined together, and readable in OWA and Outlook. There are, however, limitations to this. First off, right now this will only work for message generated by Apple iPods, iPads, or Apple Mail clients. This isn’t an accident – we developed the rules used to combine these bodies using test data from our counterparts at Apple, and while we handle messages by them well, the internet is wide and wondrous, and anyone can write messages with multipart/mixed bodies. For now this is restricted to clients we have good test data on, good rules for and a good way to identify. To create the aggregate body, we check each MIME part in the /mixed body. If a MIME part has a disposition of Attachment, it goes to the attachment well. I am not going to argue with a client that specifies that it is an attachment. If a body part has a disposition of inline or not set, if it is a plain text or html body part, we add it to the aggregate body. If the body part is an image which can be displayed inline, we add a link to it in the aggregate body. If the body part is not text, or is an image we can't display inline, it goes to the well. How do I know if this breaks me? If you're the owner of an application which is used to sending in /mixed content messages with MIME parts that you rely on Exchange treating as well attachments, and you send them from an Apple platform, and you haven’t been setting a content disposition, and the parts are text or image types (and you are setting content type), then you need to add a Content-Disposition to the MIME parts you want to be attachments, and set them to Attachment. If you're a normal consumer wondering why messages with images or signatures got split into pieces, you don’t need to do anything. -------------- end quote Well, I think that's pretty clear that this is where the problem stems from. I checked the headers on some of the emails coming in and YES, it looks like the mail with the problems is coming from Apple MAC clients: -------------- start example mail headers Content-Type: multipart/mixed; boundary="Apple-Mail-5-779600688" MIME-Version: 1.0 (Apple Message framework v1082) X-Mailer: Apple Mail (2.1082) -------------- end example mail header I think someone at Microsoft will need to get on to this issue pronto, as its going to annoy a huge number of sysadmins!

Confirmed ... removing Exchange 2007 SP3 Update Rollup 3-v2 has fixed the problem ... PDF attachments from Apple Mac clients are now being correctly received/displayed. Over to you Microsoft!