Some frequently asked questions are:
How do I pay for tnefDD?
tnefDD is free software licensed under the GPL. You can use it for free as long as you abide by the terms of the GPL.
However, if tnefDD has helped you, you should make a donation to the project. This allows the tnefDD project, and others like it, to be developed further. You can make a donation at tnefDD at, or by clicking the “Support this project” box at the bottom of the page. Note that in order to make a donation, you have to first create a user ID and password on the SourceForge site.
Why are there no attachments in the list?
TNEF files don't just contain attachments - in fact, they contain the entire e-mail that was sent. So if, for example, an RTF formatted message was sent without an attachment, there will still be a winmail.dat file containing formatting information, etc, but it will not contain any attachments. tnefDD will open such a file, but as there are no attachments, the attachment list will be empty.
How can I prevent myself from receiving TNEF files?
You can't. Whether or not you are sent TNEF files depends entirely on the settings that the person that sends the message is using. You can contact the person in question, and ask them to change their settings.
In general, two things must be true for a TNEF fle to be sent. Firstly, the sending e-mail program must believe that it is sending to a server that understands TNEF files. This typically occurs when, in Outlook, the properties of your e-mail address are set to "Send using Outlook rich text format" Secondly, the message format iself must be RTF or HTML. Note that the address property of "Outlook rich text format" is a propery of the e-mail address, NOT the message. The person that is sending the e-mail should ensure that both the "Send using..." property of your e-mail address and the format of the e-mail are BOTH non-RTF
I try to open a decoded attachment but nothing happens?
If you try to open a decoded attachment, either by double-clicking or from the context menu, and nothing happens, then no default application is defined for that type of file. First copy the file to somewhere convenient, such as the desktop, then select the file (in Finder) and select the Get Info option. Then under "Open With", select whatever application you'd like to use as a default, and click "Change All". In future, that application will be used to open all files of the type you selected.
The time stamps on the attachments are out
tnefDD does its best to preserve the "Last modification" timestamp on any attachments that it saves. However, the TNEF format, which was created in the infancy of e-mail, does not not have a consistent way to store timezone information.
Because of this timezone issue, the timestamp that tnefDD gives a file may be out to the extent that the timezone in which it was created is different to the local timezone, depending on which e-mail client sent the item, and the behavior of the servers that processed it.
There is no workround for this issue; most TNEF decoders (including Microsoft's) do not preserve file timestamps at all, and simply use the current time.