So you re sending people Winmail.dat attachments? A guide for normal people.

Transcription

1 So you re sending people Winmail.dat attachments? A guide for normal people. May 1, 2014 v1.0 Change Log: [stj May 1, 2014] Original document

2 The Problem. Eventually it happens to every Outlook user. You re going about your normal, day to day activities when somebody calls or s you to say they received an message from you with an attachment named winmail.dat. What is this? How do I open it? they ask you. Well you know that you didn t send such an attachment, and you have no idea where it came from, or how to open it and view the contents. You might also realize that you DID in fact send the recipient an with some other attachment, and that attachment is missing in action. The Explanation: The Microsoft Outlook application (aka the client ) is designed to work hand-in-hand with a Microsoft Exchange system (aka the server ) running on the network. There are certain features & functions that only make sense, and/or will only work, among recipients within the same organization, or recipients that are all using Outlook & Exchange together. These features include meeting request functionality and voting buttons, for example. The features might not make sense when applied to users outside of the organization, and as there is no way to know what server or client the recipient might be using, there is no way to know whether or not the recipient will be able to properly respond to the meeting requests or voting choices. When you send an (from your Exchange mailbox) using Outlook, the Exchange server is the computer that takes the message and sends it on its way to the ultimate destination. An analogy might be to think about a parent sending a child off on a solo plane ride. The parent buys the ticket and instructs the child (& flight attendants hopefully) where to go, but the airline is the actual transporter. In this case the parent would be Outlook, the airline would be the Exchange server. When you send an message, if the message is Rich-Text or HTML formatted meaning you can use fonts, colors, and images in the message - as opposed to Plain Text formatted, or if your message includes one or more attachments, then the Exchange server may convert all of the non-textual information about your message (the fonts, the images, the attachments, etc ) and store all of that information inside a file called winmail.dat. (Sometimes the file might be called something like ATT00001.dat rather than winmail.dat.) Recipients of the message using Outlook to view the message will usually see the message as you sent it. Recipients viewing the message using other programs (including Outlook on a Mac), or receiving the message on their smartphones for example, will instead see the plain-text of your , and either the winmail.dat attachment or possibly no attached file at all. 2

3 The Solution: Depending on the particular environment it might be possible to make changes on the Exchange server to eliminate the problem, so if possible you should request that your system administrators take care of the problem for you. You can even suggest they review this page or if that page is no longer available they can search for terms such as TNEF or WINMAIL.DAT for extensive information about the issue. Unfortunately there are times when you can t contact the Exchange server administrators, or they are unresponsive to your requests. And there might be valid reasons why the Exchange administrators can t reconfigure their Exchange system to fix the problem. DON T FRET! You can make changes yourself within Outlook to avoid the problem, and this document will show you exactly how to do so. First, we explained above that the problem involves messages that make use of formatting that s a key point to consider. The problem begins when Outlook sends a message using rich-text. The solution then, is to not send the message using rich-text. Outlook can be set up to send messages using plain-text to external recipients. There is a catch though Outlook remembers how you have sent the message to recipients in the past and will over-ride the global setting and use whatever format you used previously when sending to a previous recipient. We ll address the solution to that later in this document. First let s see how to change Outlook s default behavior: Outlook 2010, 2013: 1. Click File, then Options. 2. Click Mail on the left, then scroll down the main options window to the Message format section near the bottom. 3. There is a setting there labelled When sending messages in Rich Text format to Internet recipients: followed by a drop-down box. 4. Select Convert to Plain Text format or Convert to HTML format and click the OK button. From now on Outlook will send messages destined for external recipients using plain text or HTML, and will not convert the messages to the special format that only Outlook understands. Outlook 2003, 2007: 1. Click Tools, then Options. 2. Select the Mail Format tab. 3. At the top of the tab, in the Message format section, use the Compose in this message format: dropdown box to choose either HTML or Plain Text. 3

4 4. Click OK to close the Options dialog box. Moving forward, any new s you send to recipients that are not a part of your company should not receive any WINMAIL.DAT attachments, and should receive s as you composed them. But Wait! How do I handle contacts I ve already sent to using Outlook rich text? 1. Locate and open the contact that you want to affect. a. Start Outlook, go to Contacts (called People in Outlook 2013). i. NOTE: If using Outlook 2013 and your People open in the People view, change the view to any other. b. Find the specific contact and double-click the contact record to open it. c. Double-click the address of the contact record, and you ll see an additional options box open up: d. Select the preferred format for this specific contact, then click OK. Outlook will use that format from now on when sending to that recipient. 4

5 One more gotcha! (Or, I did the above, it STILL didn t work!...) There is one more location Outlook may have saved a preference for the sending format for a particular recipient, and that is in something called the autocomplete cache, also known as the NK2 file. As an Outlook user you know that when you begin typing an address in a new message Outlook will suggest a name/address for you that matches what you ve begun typing. You can then click on the suggested name, or press the Enter key to have the rest of the address entered for you automatically. The suggested addresses are stored in a file known as the autocomplete cache or the NK2 file. What most people don t understand is that the autocomplete entries aren t connected at all to your contacts. If: you ve set Outlook to not use Outlook rich-text format in the global options AND you re certain that the person you re sending s to isn t one of your contacts with Outlook rich text specified in the contact record AND the recipient is still receiving messages from you that are unreadable and include a WINMAIL.DAT attachment then the problem might be that the recipient is saved in your autocomplete cache and is remembering the Outlook rich-text setting there. Solution compose a new message to this person. When you begin entering the address and the autocomplete suggestion pops-up as you type, CLICK THE X NEXT TO THE SUGGESTED NAME/ ADDRESS, and finish typing the recipient s address manually. Before sending the message, check the options of the message and make sure the message is set to use either HTML or Plain Text - and then Send the message. That will result in the recipient being re-added to your Autocomplete, stored with the sending format you specified on the message. 5