.MS-TNEF File Extension

MS Transport Neutral Encapsulation Format

Developer Microsoft
2.7  |  3 Votes

What is an MS-TNEF file?

File sometimes generated by Microsoft email programs such as Outlook; saves the message in Microsoft's proprietary TNEF format, which often is not recognized by other email programs; may cause the email to appear with the "application/ms-tnef" text, which is the MIME type for Microsoft Exchange email formatting.

More Information

NOTE: MS-TNEF files are rarely seen with the ".ms-tnef" extension. Instead, they are usually seen with the filename Winmail.dat (.DAT file), which includes the MS-TNEF encoded data.

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Programs that open MS-TNEF files

Included with OS

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