winmail.dat - any way to fix this issue from the mac (receiver) side?

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winmail.dat - any way to fix this issue from the mac (receiver) side?

A user, probably using Outlook on a PC is sending a message to two users on Macs, running the same version of Mac OSX and the same version of the Apple mail client Mail.app. One of the Mac users receives the message as intended with formatted text and attachments showing up normally. The other Mac user receives the message and can see only the body text of the message and any attachments or other formatted text in the messages shows up as a single "winmail.dat" attachment.

The two Mac users have combed through every available setting in Mail>Preferences as well as the settable view options in the app but can not find any discrepancy that accounts for this, nor any way to resolve the issue. One user can read the incoming message normally, the other user is essentially out of luck.

The user who's having the problem has an iCloud mail account BTW, so (at least one would hope) the difference can not be explained by something that her ISP is doing to "corrupt" incoming mail.

Searching for help on this issue, I find tons of content that talks about how the PC user can change settings to mitigate the problem. In this case, however, the same message can be read by one Mac user but not another, so I'm really hoping to find a fix for this on the Mac side by asking in Apple support communities.

Posted on Sep 1, 2019 8:55 AM

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Answer 1

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VikingOSX

Level 10

123,512 points

Sep 1, 2019 9:23 AM in response to David Duff

The article that John offered a link to does not actually link to an application that can handle the winmail.dat files. One free example that has been around for years is TNEF's Enough. You can find others by searching for tnef in the Mac App Store search window. I used to drag this product from my Applications folder onto the Dock directly below the Mail application for drag and drop solutions.

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Answer 2

John Galt

Level 10

155,882 points

Sep 1, 2019 9:10 AM in response to David Duff

Please read If your email contains a winmail.dat attachment - Apple Support.

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Answer 3

MrHoffman

Level 10

146,803 points

Sep 1, 2019 12:10 PM in response to David Duff

Please read the support article.

There are two copies of the message being sent here. One recipient address is listed as foreign in the sender's configuration and the mail message copy to that recipient is getting handled correctly—whether that configuration setting was by the sender, or by the folks that are administering the mail server for the sender—and the other mail recipient is listed as non-foreign and as running Windows and thus appropriate for receiving the winmail.dat file.

Per a Microsoft representative, "...there is no option for external recipient’s side to change the message format to prevent Winmail.dat attachments."

Also per Microsoft: https://support.microsoft.com/en-us/help/2487954/how-to-specify-the-email-message-format-that-s-used-for-external-recip (This sequence is for Microsoft Exchange Online. There are different sequences for the other Exchange Server products.)

Short of adding code into mail clients all over the Internet to deal with this Microsoft mail extension—or post-processing the mail message with a separate tool, as has been suggested—this is widely treated as a Microsoft server and/or sender configuration error.

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