attachments showing as Winmail.dat, works fine in Entourage

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Hi Experts

I am having a very annoying issue in, certain customers send me emails with word, excel, powerpoint attachments and all i receive is a Winmail.dat file as an attachment.

This problem doesn't happen when they same email with attachments is opened in Entourage for Mac.... any ideas how i can solve this?

I have read lots of articles on getting the sender to change their settings, but this isn't a practical solution. v4.3 (snow leopard) and connects to an Exchange 2007 server.

Would appreciate any advice on how this can be sorted.

Many thanks

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Top Expert 2010

Hi Justin

Please check this kb from apple.

Why this is happening.
the sender is using Outlook Rich Text format to send you emails.

Ask them to use HTML / plain text
In outlook
Go to Tools / Options / Mail Format
Change it to HTML from Rich Text

When you send it using Rich Text - Outlook sends the formatting data of the message in Winmail.dat file.

Hence the attachment.


Thanks Sunnyc7

Unfortunately that doesn't really solve the problem for me, as i can't realistically contact eveyone who is trying to send me an email and ask them to resend using those options, as mentioned in my original post).

So is it that there is no way for Mail.App to read Outlook Rich Text format, therefore i need to change to Entourage to solve the problem?

Top Expert 2010

2 things.
a) This problem is largely exhibited by various versions of - 2 /3 /4.
the apple support cases are also for

b) However that being said, I really dont know if this will go away if you upgrade to entourage. I dont have any info. there.
you can do a trial download and see if this works and re-import the emails and see if the problem recurs.

Chances of winmail.dat going away in Entourage 2008 is high - because as microsoft mail products dont need to send formatting details to other ms mail products (this is my guess....not a documented support case :-) )

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Thanks Sunnyc7

Upgrading (or should i say downgrading) to Entourage does solve the problem as a colleague of mine in the same office runs Entourage with identical setup to myself and everything works fine for him.

Its just frustrating that formatting aside that the file attachments to the email also get blocked and replaced by winmail.dat, i'm only really interested in the attachments not the formatting!!

I will leave the question open for a few days to see if i gain any other insights, failing that thanks Sunnyc7 for your help and the points are yours!!

Top Expert 2010

Thanks Justin :-)


To make it clear, the problem is NOT!

The problem is that MS Outlook zip's up all attachments into the winmail.dat file in a 'proprietary' container and expect the rest of the world to be able to unzip it by magic!

Yes, Entourage knows how to handle winmail.dat files.. surprice! But this is (at best) not a job for the mail client in the first place, as the Sending mail client (Outlook) should Never-Ever encode the attachments in the first place!

Anyway, as far as I know - Exchange has a 'decode winmail.dat files for the client' setting somewhere, but I guess you need to connect via IMAP... but maybe that is not nessesary..

I know Kerio Mailserver does server-side decoding for the clients...

And to be honest: Yes, you need to tell those (stupid) people using Outlook to use a modern format for sending!
There are two ways to treat this:

Locally with this Software
or online on this URL: (there is a maximum of 5 MB)

There is currently no way can handle this as the previous statements say.


Although not ideal this did the trick

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