ATT file shows up as attachment

since it is a .html file, open it and post what is in the file. It might help the forum to explain it.

Does it only happen in the office?
The office probably uses Exchange Mail Server.

so if you send an email to an outside Mac person it doesn't happen
but if you send an email to a PC person in OR out of the office it happens?

If so then check with the IT people, there's probably a setting they can change with Exchange.

Microsoft seems to be aware of this. At least when this file ATT00001.html or ATT00001.txt appears in outlook. Maybe it is related when a msg is send from outlook to OSX mail as well? Can someone check this?
http://support.microsoft.com/?kbid=312351

One thing to do is to make sure that any attachment is included after all body text including your signature. If the Exchange server sees any text after the attachment, it will split that text off into another attachment.

Hope this helps.

I've had this problem too and it still happened even with "Send Windows-friendly attachments" and setting attachments to appear after the signature. I send mail through an Exchange server, but I can see the extra attachment when I view my sent mail in Mail. I just tried un-checking the signature setting for making the signature in the default message font and this seems to be working for now. That is, the "Always match my default message font" box is no longer checked. It may be worth trying.

This seems to be one of those voodoo issues that nobody really is able to understand or fix. It's not accurate to say that the attachment problem is only visible to those using Outlook, because I can see the extra attachment in my sent mail folder in Mail. On the other hand, if I send these emails to Gmail or Yahoo, they don't display any extra attachments when the message is received there.

After moving to Exchange in the workplace (accessed via IMAP) I experienced this problem for weeks under Leopard's Apple Mail, and was unable to find a solution. Since my upgrade to Snow Leopard, I am happy to report that this oddity seems to have been fixed somehow.

I tested this by opening my Inbox in Apple Mail on two different machines simultaneously: one with Leopard, and one with Snow Leopard. I then created a simple message in each client and sent it to myself, and viewed each of these on both machines. The result?

The message I generated in Apple Mail 3.6 showed an ATT file as usual when viewed in that client. However, I no longer see these ATTxxxxx.htm files along with any messages on 10.6. No such files are created when authoring new messages in Apple Mail 4.1 either - even when viewing them on my OS X 10.5 machine, I don't see anything out of the ordinary.

So for what it's worth, _moving to OS X 10.6 seems to have corrected this glitch for me_, and may do the same for you.

(One further oddity worthy of mention - in a few posts on this subject I have seen suggestions that placing attachments at the very bottom of a new message and eliminating any text below them might prevent the creation of these extra files in Apple Mail. When I failed to do this in Leopard, the received message was entirely empty on the Snow Leopard machine; no visible body text, and seemingly no way to see the attachment. Perhaps a bug relating to the repair of the first glitch...)

Unfortunately we have the problem on a 10.6 install here. This is happening on only on 1 out of 8 mac in the office though. All messages with attachments opened on a PC using Outlook (2007) appear as an attachment or nothing at all.

Same to me! I already send windows friendly attachments, but no solution.

The same here.

I'll add a "me too". SL 10.6.2. Whenever I send mail to someone on MS Exchange that file shows up. Very frustrating and it makes us appear unprofessional. Hopefully someone can help.

I am surprised that this issue has still not been addressed buy Apple, as most of our customers are using PC's it is Embarrassing to have an Email fragment in such a manner. Have tried numerous fixes, taken the machine to the apple store ( no luck their although they did try to help ). So the question is can it be fixed or do we need to be windrones.

This has been driving me nuts for over a year, and I've never been able to get a straight answer about whether this is more an issue with Exchange or Mail.

But I do have a work-around: Select "Always Insert Attachments At End of Message" from the Edit -> Attachments menu. You won't be able to have images, etc, inline in your messages, but at least the message won't fragment like that.