I have 2 users that occasionally receive emails with a pdf attachment that is not actually on the email. The paperclip will show in outlook but there is actually nothing attached. Accessing via owa shows an attachment but it appears corrupt.
I know the email is getting through our barracuda email filter because I can see it and download it from that dashboard with no problem.
Also, sending the exact email+attachment to a personal email address I have works fine. When I forward that email with the attachment to the users it also works fine.
Currently leaning towards it being an issue with outlook as opposed to exchange or barracuda spam filter but I could be wrong. A fair amount of google searching has turned up nothing, mainly issues with Outlook Express.
Also, corrupt attachments don't seem to be coming from any specific people, but when one won't come through resending doesn't resolve either.
If anyone has any ideas on this matter I would greatly appreciate it.
Best Answer
This was a well hidden KB article and I only found it on some old technet post.
Turns out it has to do with how some email clients form MIME-encoded messages that have inline attachments. Issue was resolved by running this command on Exchange Server 2007.
set-OrganizationConfig -ShowInlineAttachments:$true
However this is a little tricky as the reason that is off by default is because it does pose a minor security risk. I think at this point I'll leave it disabled and investigate on a case by case basis as it only happens on a very few select incoming emails. Wondering if anyone has any experience enabling this and if there is any arguments for or against it.
Links that support the resolution:
http://support.microsoft.com/kb/954684
http://social.technet.microsoft.com/Forums/en-US/exchangesvrclients/thread/478c326b-486b-461c-9141-dd544b245c75