You don't mention how the messages are being retrieved, but I have seen this before with Exchange 2007 and IMAP retrieval (though I believe it affects POP3 as well).
Have a look at this Technet document, specifically the
ImapMessagesRetrievalMimeFormat switch. The documentation is exceedingly vague, but Exchange can force the format of the messages as they are retrieved from the server, either by user (as the link indicates) or on the service itself; in which case you would use the
Set-ImapSettings command, and change the
The current setting for the service on your host can either be seen using PowerShell using the following and looking for 'MessageRetrievalMimeFormat':
Get-ImapSettings | fl
Alternatively you can use the GUI:
- Expand 'Server Configuration'
- Expand 'Client Access'
- Select the server that you want to manage, then the 'POP3 and IMAP' tab
- Get the properties of the appropriate connector and examine the 'Retrieval Settings' tab. The MIME format for the connector in question can be seen/changed in the 'Message MIME format' drop-down box at the top of this box.
A similar thing can be done for individual mailboxes by getting the properties of the mailbox and looking at the 'Mailbox Features' tab.
I can't tell you what setting is correct for your situation (as the documentation is so vague), but my Exchange 2007 installation has the setting left on 'Best Body Format'.