Das Phänomen winmail.dat
1 ACT-Knowledge base
http://kb.act.com/app/answers/detail/a_id/39176
Emails sent through Outlook are recieved without formatting and have a "winmail.dat" attachment
Symptom: Emails that are sent through Outlook appear without formatting in recipient mailbox, and have an attachment titled "winmail.dat"
Cause:
This issue can be caused by a setting in Microsoft Outlook that enables a type of formatting (TNEF Encoding) used when sending emails between Microsoft email clients. When an email formatted as such is received by a non-Microsoft email client, the email appears unformatted, and the formatting data is attached as a "winmail.dat" file.
For information on managing this setting please see the article below:
https://support.microsoft.com/en-gb/hel ... in-outlook
Please note: This article is provided by Microsoft and is linked here purely for your convenience.
…………………………………………………………………………………………………………………………………………………………..
2 Microsoft
https://support.microsoft.com/en-gb/hel ... in-outlook
2.1 Summary
Both Microsoft Outlook and the Microsoft Exchange Client sometimes use a special method to package information for sending messages across the Internet. This method is technically known as Transport Neutral Encapsulation Format (TNEF).
The use of TNEF is typically affected by settings in Outlook that are known as Microsoft Outlook Rich Text Format (RTF). RTF and TNEF are closely related, but not the same.
A TNEF-encoded message contains a plain text version of the message, and a binary attachment that "packages" various other parts of the original message. In most cases, the binary attachment is named Winmail.dat, and may include the following information:
- The formatted text version of the message (for example, font information and colors).
- OLE objects (for example, embedded pictures and embedded Microsoft Office documents).
- Special Outlook features (for example, custom forms, voting buttons, and meeting requests).
- Regular file attachments that were added to the original message.
Some Outlook features require TNEF encoding to be understood correctly by an Internet email recipient who also uses Outlook. For example, when you send a message that has Voting buttons to a recipient over the Internet, if TNEF is not enabled for that recipient, the Voting buttons are not received. Or, for sending messages that have regular file attachments, TNEF is not needed. If you are sending messages that have file attachments to a recipient who does not use Outlook or the Exchange Client, we recommend that you manually choose to use an email format which does not require TNEF (such as HTML or plain text). If a message is sent without TNEF, the recipient can view and save the attachments as expected.
2.2 Sending and receiving concerns
When an email client that does not understand TNEF receives a message that contains TNEF information, the following are the two common results:
The plain text version of the message is received and it contains an attachment named Winmail.dat. The Winmail.dat attachment has no useful information when it is opened because it is in the TNEF format.
The plain text version of the message is received and it contains an attachment that has a generic name such as ATT00008.dat or ATT00005.eml. In this case, the client is unable to recognize either the TNEF part of the message or the Winmail.dat file name. Therefore, a file name is created to hold the TNEF information.
In addition to the receiving client, it is common for an email server to strip out TNEF information from messages as it delivers them. If a server option to remove TNEF is turned on, clients will always receive a plain text version of the message. Exchange Server is an example of an e-mail server program that has the option to remove TNEF from messages.
2.3 Message encoding
The Internet standards for encoding messages such as Multipart Internet Mail Extensions (MIME) and UUENCODE are used independently of TNEF. TNEF can exist in a MIME-encoded message as a MIME body part of type "application/ms-tnef," or in a UUENCODED message as an attachment named Winmail.dat. The sent TNEF encoding must be understood by the receiving client to correctly display the encapsulated information.
2.4 How to control TNEF in messages
You can control TNEF by using one of three methods:
-Global - If you change your default email format to plain text or HTML, it helps make sure that TNEF is not sent unless an Outlook feature needs it.
- Per Recipient - You can specify in the recipient's email address not to send TNEF so that a recipient always receives plain text versions of the message.
- Per Message - When you compose a new message, or reply to a received message.
Method 1. How to make a global change for TNEF
For Microsoft Outlook 2010 and later versions:
To turn off TNEF, follow these steps:
Click the File tab, click Options, and then click Mail.
In the Compose in this message format list, click Plain Text or HTML, and then click OK.
2.5 Common Scenarios
Problem: Recipient receives the Winmail.dat attachment.
Solution: Turn TNEF off (either for the recipient, or globally).
2.6 Deutsch (stark gekürzt, aus automat. Übersetzung von Microsoft)
https://support.microsoft.com/de-de/hel ... in-outlook
Zusammenfassung
Microsoft Outlook und Microsoft Exchange Client verwenden manchmal eine spezielle Methode zum Packen von Informationen zum Senden von Nachrichten über das Internet. Diese Methode wird technisch als Transport Neutral Encapsulation Format (TNEF) bezeichnet.
Die Verwendung von TNEF normalerweise Einstellungen in Outlook betrifft, die als Microsoft Outlook Rich Text Format (RTF) bezeichnet werden. RTF und TNEF sind eng miteinander, aber nicht verbunden. Eine TNEF-codierte Nachricht enthält eine nur-Text-Version der Nachricht und eine binäre Anlage, die verschiedene andere Teile der Originalnachricht "Pakete". In den meisten Fällen hat die binäre Anlage den Namen "Winmail.dat" und kann folgende Informationen enthalten:
Die formatierte Textversion der Nachricht (z. B. Schriftartinformationen und Farben).
OLE-Objekte (z. B. eingebettete Bilder und eingebettete Microsoft Office-Dokumente).
Besondere Outlook-Features (z. B. benutzerdefinierte Formulare, Abstimmungsschaltflächen und Besprechungsanfragen).
Normale Dateianlagen, die die ursprüngliche Nachricht hinzugefügt wurden.
Senden und Empfangen von TNEF
Wenn ein e-Mail-Client, der TNEF nicht versteht, eine Nachricht erhält , die TNEF-Informationen enthält , sind die zwei folgenden Ergebnisse möglich:
Die Textversion der Nachricht wird empfangen und enthält eine Anlage mit dem Namen "Winmail.dat". Die Anlage "Winmail.dat" hat keine nützlichen Informationen ist TNEF-Format öffnen.
Die Textversion der Nachricht wird empfangen und enthält eine Anlage mit dem generischen Namen wie ATT00008.dat oder "ATT00005.eml". In diesem Fall kann der Client TNEF-Teil der Nachricht oder den Namen Winmail.dat-Datei erkannt. Daher wird ein Dateinamen für die TNEF-Informationen erstellt.
Steuern der TNEF in Nachrichten
Wie Sie eine globale Änderung für TNEFdurchführen
Für Microsoft Outlook 2010 und höher:
Gehen Sie folgendermaßen vor, um TNEF zu deaktivieren:
Klicken Sie auf die Registerkarte Datei , klicken Sie auf Optionen und klicken Sie auf E-Mail.
Klicken Sie in der Liste Verfassen im Nachrichtenformat auf nur Text oder HTML, und klicken Sie dann auf OK.