Microsoft Exchange Server and file attachments: a follow-up

Several users havereplied to our previous coverage on Microsoft Exchange Server failing to handle file attachments for Mac clients properly.

Confirmation: other users affected William Richards writes: I thought I was the only one with this problem, but it seems someone else has it too. I use Entourage and whenever I get a mail from a certain client of mine who uses Microsoft Exchange Server, any attachment is shown as having a mime type of "microsoft tnef". This drove me nuts for a while until I discovered the application TNEF's Enough Classic.

TNEF: an explanation and workaround Joshua Jacob created an application named TNEF's Enough that works around the problem. TNEF's ReadMe file also has an explanation of what is happening. Here is an excerpt:

"TNEF's Enough allows Macs to read and extract files from Microsoft TNEF stream files. The files are usually received by SMTP based e-mail programs from Microsoft Exchange and Microsoft Outlook users. The SMTP based e-mail program will usually either receive a MIME attachment named 'winmail.dat' or a MIME attachment with the type 'application/ms-tnef.'

The file is a rich text (or MAPI) message that is sent from Outlook to Exchange. When Exchange sends the message to an outside server it writes the MAPI message as a MIME attachment. The unfortunate side effect of this plan is that if the Outlook user has someone in their address book as a person who can receive 'Rich Text' then the user will receive the TNEF file whether the user uses Outlook or not."

Server configuration also a factor? Gordon Strong writes: "This may be a configuration problem on the Exchange server (depending on the version). I ran into something very much like this under Exchange 5.5 using Outlook Express as an IMAP client. The solution was to clear the Use Microsoft Exchange rich-text format box on the IMAP4 Message Format properties tab on the Exchange server (this is an admin/server fix, not a client fix). This Technet article has more. The article suggests this fix is only for Outlook Express, but it might be something to check."

Update: Jim Clements writes: "Another work-around is to send files using binhex."