Opening winmail.dat files

We keep getting e-mail attachments in winmail.dat files, and can’t open them. What’s going on? Is there a utility that can extract the attachments from these?

We keep getting e-mail attachments in winmail.dat files and can’t open them. What’s going on? Is there a utility that can extract the attachments from these?

When Outlook or Outlook Express users send e-mail composed using Rich Text Format, the attachments often get transmitted in winmail.dat form, which contains the material in ms-tnef format. Many other mail clients cannot unpack these. Often, Outlook Express can’t open them either. The Microsoft Knowledge Base answer is to have the sender resend the e-mail in plain text format. There are tools that can retrieve your documents from the winmail.dat file. A Web-based extractor (https://tud.at/php/tndef/) lets you upload the winmail.dat attachment and have the extracted file returned. You also can download the software the service uses under the general public license. A desktop utility called tnefclean is available at https://www.dread.net/~striker/tnefclean/. Another utility, WMParser, is free at https://www.magicwinmail.net/wmparser/. For Linux systems, the Debian version can be installed with the command “apt-get install tnef.” A Web search on “tnef” or “winmail.dat” will provide other extraction tools.

Blass is a network architect at Change@Work in Houston. He can be reached at dr.internet@ changeatwork.com.