Sometimes individuals on UBmail Powered by Exchange send
messages that contian a file called Winmail.dat that some other
email clients can't open properly. See how to configure Outlook to
not send those files.
Outlook can use a method called Transport Neutral Encapsulation
Format (TNEF) to package information for sending messages. The use
of TNEF is affected by settings in Outlook that are referred to as
Rich Text Format (RTF).
A TNEF-encoded message contains a plain text version of the message and a bundled binary attachment that contains the other parts of the original message. This attachment is named Winmail.dat, and includes:
Unfortunately, the Winmail.dat bundled attachment is not readable by many other email clients or by Outllook for Macintosh and it may even appear to the recipient as though the expected attachment is missing.
Set the Global Properties to have Outlook by default send your email in Hypertext Markup Language (HTML):
Meeting requests or voting buttons may not work with this setting, but you can override the format on select messages.
You can clear your cache settings for a person if they are still receiving Winmail.dat files from you. Create a new message, begin to enter the email address, then use the arrow keys to scroll up or down, highlight the address of the person and press the delete key to remove the entry. Enter their address in the To field and it will create a new entry.