We have a strange situation that I am trying to resolve.
One of our users is reporting that some emails that contain attachments are not coming through to them. After some investigation it appears that they do infact recieve the emails but the attachment is missing.
I check the message tracking logs and what appears to be happening is that the server recieves an email, which is then forwarded to the correct mailbox. A couple of minutes later another email, from the same sender is recieved - but this is much larger so I'm assuming contains the attachment. This email has the same messageId as the previous email and as a result appears not to be delivered to the users mailbox, instead being marked with an EventID of DUPLICATEDELIVER.
Can anyone shed any light on the situation?