winmail.dat issue

Nathan Lindley
Nathan Lindley used Ask the Experts™
Hi Experts,

I have a mac user who is receiving any email with an attachment, with a 'winmail.dat' attachment. REGARDLESS of whether the sender sends as plain text, HTML or rich text. Has anyone come across this?

Mac OS X 10.7.5
Mail Version 5.3 (1283)

Regardless of email text format, the attachment is coming through as winmail.dat.

Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
This is a long-standing issue with OSX and Microsoft Exchange.  Basically it is a problem with the way Exchange formats email attachments and the way Apple Mail interprets them.  If you cannot edit the Exchange settings then changing email client to MS Outlook for OSX is one option.

Can you confirm the MS Exchange version you are using as there are settings in Exchange which can be used to address this issue?

Also, that is a very old version of OSX .. is there any prospect of upgrading the OSX version and Apple Mail as this can improve issues with SOME versions of Exchange.

In the meantime you can use a version of TNEFs Enough to open winmail.dat files.
IT Support Engineer
This was a setting in the 'Mail Contact' in Exchange 2010, under the general tab, there is a setting for "Use MAPI rich text format" which was set to "Use Default Settings" - I changed this to "Never"

This resolved the issue
Nathan LindleyIT Support Engineer


Researched this issue further on the internet due to this being an urgent matter.

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial