OL2000: Attachments Not Visible to Some Recipients When Using TNEF

You send e-mail with attachments to a recipient who does not use Outlook to read e-mail. When the e-mail message is opened, the attachments are missing.

The receiving e-mail client does not understand the internal Outlook packaging of the attachment information known as Transport Neutral Encapsulation Format (TNEF).

Set your default mail format to either Plain Text or HTML. These formats do not encode attachments in the TNEF format. You can specify not to use TNEF for a particular recipient by using the methods in the "More Information" section.

When using Plain Text or HTML as your message format, you are still free to attach files of any type to the message. The attachments will be successfully delivered to non-TNEF aware clients.

You will not be able to attach Outlook items, an Outlook contact for example, since Outlook items are special Outlook data that require TNEF, rather than regular file attachments.

To Turn Off TNEF Encoding for Internet Mail Only Installation

For All Outgoing Messages

1. On the Tools menu, click Options, and then click the Mail Format tab.
2. In the Send in this message format list, click to select Plain Text or HTML, and click OK.

On a Per-Recipient Basis

1. Create an Outlook contact for the recipient if one does not already exist.
2. Type the e-mail address of the recipient in the E-mail field.
3. Click to select Send using plain text, and then click Save and Close.

To Turn Off TNEF Encoding for Corporate or Workgroup Installation

For All Outgoing Messages

1. On the Tools menu, click Options, and then click the Mail Format tab.
2. In the Send In This Message Format list, click to select Plain Text or HTML, and click OK.

On a Per-Recipient Basis

In the Contact Folder

1. Open the recipient's record in the Contacts folder.
2. Double-click the recipient's e-mail address.
3. Click to clear Always send to this recipient in Microsoft Outlook rich-text format, click OK, and then click Save and Close.

In the Personal Address Book

1. Locate the recipient in the Personal Address Book.
2. Double-click the recipient's e-mail address.
3. Click to clear Always send to this recipient in Microsoft Exchange rich text format, click OK, and close the address book.

For additional information about TNEF, click the article number below to view the article in the Microsoft Knowledge Base: