TNEF File
What are TNEF files and how to open them
Are you having problems opening a TNEF file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your TNEF files.
What is a TNEF file?
A .TNEF file is a Transport Neutral Encapsulation Format file.
TNEF stands for Transport Neutral Encapsulation Format. It’s an email attachment format that Microsoft created to allow sending files in a universal binary format. TNEF is also known as Outlook Rich Text Format. Microsoft Outlook uses TNEF to send attachments. Microsoft Exchange Server also uses it.
Email attachments sent using this format are usually named "winmail.dat" and are therefore saved with the .dat file extension instead of .tnef. You can find various winmail.dat openers on our page about file extension DAT.
How to open TNEF files
We have identified one TNEF opener that is compatible with this specific type of TNEF file.
Programs that open Transport Neutral Encapsulation Format files
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Last updated: February 24, 2023
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