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How do I open Winmail.dat?

How do I open Winmail.dat?

iPad 2 Wi-Fi + 3G, iOS 7.1

Posted on Apr 8, 2014 11:05 AM

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Posted on Apr 15, 2014 8:05 AM

In my case this appears to be a phone issue. I have two iPhone 5's. One receives the images and attachments fine. The other doesn't. Both are on the same version of the OS. Emails were sent to test from Outlook in all three available formats (RTF, Text, HTML) and also from Gmail. In all cases, one received the attachments fine and the other didn't.


Please help.


Thank you,

Amy

11 replies
Question marked as Top-ranking reply

Apr 15, 2014 8:05 AM in response to Texas Mac Man

In my case this appears to be a phone issue. I have two iPhone 5's. One receives the images and attachments fine. The other doesn't. Both are on the same version of the OS. Emails were sent to test from Outlook in all three available formats (RTF, Text, HTML) and also from Gmail. In all cases, one received the attachments fine and the other didn't.


Please help.


Thank you,

Amy

Apr 15, 2014 8:26 PM in response to ajlayne

ajlayne wrote:


In my case this appears to be a phone issue. I have two iPhone 5's. One receives the images and attachments fine. The other doesn't. Both are on the same version of the OS. Emails were sent to test from Outlook in all three available formats (RTF, Text, HTML) and also from Gmail. In all cases, one received the attachments fine and the other didn't.


iPhone doesn't know from the winmail.dat files, it just receives and (tries to) display whatever was sent. Not having support for the Microsoft Windows winmail.dat message format, you'll just get an attachment that's not viewable. With this case, it is the sender and the sending program chooses whether to send HTML or text format messages, or WINMAIL.DAT files, and that's the key detail here. It's all on the sending application.


For your reported behavior, are the messages to both phones using the exact same target email address? Because that's how the Windows mail client makes this determination; on whether or not to send a Windows-format mail message. This choice uses the sender's settings for the receiving email address. If your tests are sending to different email addresses to reach those two phones, there's the trigger — the settings for the two addresses differ in the Microsoft Windows software you're working with. As an alternative test, try using Thunderbird or another mail client, and see if sending mail to the addresses works as expected.


Apr 16, 2014 6:16 AM in response to MrHoffman

In Outlook, I changed the setting for how the mail sent to each typoe to resolve the issue. I created one email per setting and addressed to both people on their corporate exchange account (same server for both) and their gmail accounts. This is where the confusion arose since one phone receives fine and the other doesn't. I used Gmail as an alternate mail client with the same result.


So basically I used two different clients each time sending to four addresses two are located on each phone. Phone A always receives a winmail.dat file no matter which client or email address is used. Phone B always receives the attachment in it's correct format.


I took it a step further and used the phones to test sending. Even if I use Phone A to send to the other account on Phone A, winmail.dat is received. If done from Phone B to Phone A, Phone A winmail.dat persists. Phone A to Phone B correct format is received. I'm thinking there is a setting somewhere on Phone A I'm not aware of that was somehow changed since it is not mail client dependant nor recipient mail server dependant based on the testing results.

Apr 16, 2014 8:51 AM in response to ajlayne

ajlayne wrote:


In Outlook, I changed the setting for how the mail sent to each typoe to resolve the issue. I created one email per setting and addressed to both people on their corporate exchange account (same server for both) and their gmail accounts. This is where the confusion arose since one phone receives fine and the other doesn't. I used Gmail as an alternate mail client with the same result.


So basically I used two different clients each time sending to four addresses two are located on each phone. Phone A always receives a winmail.dat file no matter which client or email address is used. Phone B always receives the attachment in it's correct format.


I took it a step further and used the phones to test sending. Even if I use Phone A to send to the other account on Phone A, winmail.dat is received. If done from Phone B to Phone A, Phone A winmail.dat persists. Phone A to Phone B correct format is received. I'm thinking there is a setting somewhere on Phone A I'm not aware of that was somehow changed since it is not mail client dependant nor recipient mail server dependant based on the testing results.



This is a Microsoft Windows setting with Microsoft Outlook or within the Exchange Server gateway in general. These winmail.dat files have been arriving on Linux, BSD, OS X, Tru64 Unix, ULTRIX, Solaris and many other servers for many years, too — unfortunately, everybody that's using non-Microsoft clients and tools encounters these files from time to time. The winmail.dat is a Windows Mail data file, after all.


If the mail client or if the mail server gateway sends a mail message to an iOS device — or many other "foreign" mail clients — that involves a winmail.dat file generated by the sending client or generated by the originating mail server gateway, then iOS will show the winmail.dat file. Like many other mail clients, the iOS mail client does not decode, process nor create these winmail.dat files. (Most clients simply treat these winmail.dat files as an arbitrary attachment on the message.)


Send the same messages to the same email addresses and read those messages via another mail client — one that doesn't have winmail.dat support — and you'll see the exact same behavior; a wad of attached winmail.dat data.


From Microsoft: How to Prevent the Winmail.dat File from Being Sent to Internet Users. In short, either the Outlook client settings or the Exchange Server (IMC) settings will need to be changed here.

Apr 16, 2014 11:29 AM in response to MrHoffman

Mr. Hoffman,


Thank you for trying. This is quite frustrating.


I must be missing something she receives attachments this way from all senders to all three of her email accounts on her iPhone. If she opens it at the computer or on her iPad the attachments are fine. It's only on her iPhone. Also, out of 60+ people in my office, she's the only one with the issue. We don't have access to the exchange server and Outlook settings have been changed per the above several times before and after I posted. This person receives hundreds of emails and I find it hard to believe that every sender is using an Exchange server with the wrong settings or that Gmail's settings are wrong. Sending her to the Apple store for help. She most likely clicked or deleted something on the phone that caused this.

Apr 17, 2014 8:56 AM in response to ajlayne

Compare the settings of the iPad and the iPhone devices — wondering if the "computer" referenced here is actually a Microsoft Windows computer running the Microsoft Outlook, Outlook Express tool or some other Microsoft mail client, and thus likely to respond correctly to receiving a winmail.dat file — and particularly if the two iOS devices are configured differently; one configured to SMTP (and POP or IMAP) and one configured to Microsoft Exchange. If the two iOS devices are consistent and/or configured for SMTP (and POP or IMAP), then there's something really weird with the sending client or sending mail server, or there are different email addresses.

May 2, 2017 10:45 AM in response to ajlayne

Did you ever find a solution for this? We've just recently had it happen on an iPad after it updated the OS. The setting in Outlook haven't changed and no one else is having an issue receiving the attachments. Even other Apple products are receiving the attachments fine. It's just this one iPad that is having the issue. I can't find which setting is set differently.

Thanks,

Jessica

How do I open Winmail.dat?

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