".doc" in Mac mail attachment changed to ".dat" when receved by Windows.

Question

".doc" in Mac mail attachment changed to ".dat" when receved by Windows.

Sometimes (but not always!) a Microsoft Word doument with .doc extension attached to email in IMAC Mail shows up in Windows Computer Outlook Express with a .dat extension and will not directly open. I've seen previous posts address a similar problem but quite this. The frustration is the inconsistency of the problem.

Will appreciate any suggestions.

Charles

IMAC G5 Mac OS X (10.4.2)

IMAC G5, Mac OS X (10.4.2)

Posted on Oct 21, 2006 9:02 AM

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Answer 1

Oct 21, 2006 9:37 AM in response to Charles Wyatt

Hi Charles! 😀

Have you tried sending "Windows friendly attachments?" Also if you're really running 10.4.2 you might want to update just in case... 😀

Post back ok?

Reg...

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Answer 2

Oct 21, 2006 10:02 AM in response to Charles Wyatt

Charles,

Are you sending with an account and SMTP associated with a MS Exchange server? If not, what type of account do you have, and who is the provider of the SMTP being used as Outgoing Server?

Ernie

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Answer 3

Oct 21, 2006 10:47 AM in response to Ernie Stamper

I am sending froma POP account via Verizon.net

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Answer 4

Oct 21, 2006 11:18 AM in response to Reggie Ashworth

I really am running OS 10.4.7. I have tried checking the Windows Friendly button, but doesn't seem to make a difference.
Thanks for your interest,
Charles

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Answer 5

Oct 21, 2006 12:44 PM in response to Charles Wyatt

Charles,

Are you sending via the Verizon provided SMTP, then?

Are you using Rich Text Format to compose your emails, and are you using a Signature?

I my experience, and opinion, it would not be Mail that is making this change, but rather somewhere in the path of servers before the message gets to the recipient. The questions above are meant to check for things which might trigger some server to make this change.

Ernie

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Answer 6

Oct 21, 2006 5:38 PM in response to Ernie Stamper

I am using the Verizon.net SMTP. My Composing Preference is set for Rich Text, and I do not use a Signature. The puzzling thing to me about the problem is that it is intermittent. After receiving notice from a couple of Windows user that they couldn't open a Word document I had sent (it was .dat format), I tried sending the same document as an email attachment from my MAC to a Windows computer which uses Outlook Express several different times. Sometimes (less than half) the attachment would have a .dat extension, but other times would show up with .doc and Word icon, opening up normally. I can't figure out how to force the error to happen.

Thanks so much for your helpful advice.
Charles

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Answer 7

Oct 21, 2006 6:03 PM in response to Charles Wyatt

Charles,

Does this happen when sending the attachment via new message, not in a reply or forward?

If not too private, can you open a message that has been sent to both your PC, and your Mac, click on View in the Menubar, place the cursor over Message and choose Long Headers. With the Long Headers in full display, please forward to me at the address that can be found in the bio line of my Profile (click on my name to see).

Feel free to try and get the error to happen with an email to me. While I might see the same things a PC recipient, when I observe the message in Raw Source, I can tell a great deal about what they probably would see.

Ernie

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Answer 8

Oct 21, 2006 8:10 PM in response to Ernie Stamper

Ernie,
The problem has only been observed on a new email with attached Word document.

Will try to forward you example of attachment with .dat conversion error, from Windows machine (different email than one on the Forum profile). The msg was sent from Mac 10.4 to Windows XP Outlook Express. I will also forward another email with same attached word document that came thru as .doc OK, just for comparison
Hope it will tell you something.

Thanks,
Charles

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Answer 9

Oct 21, 2006 8:25 PM in response to Charles Wyatt

Charles,

I look forward to these tests. However, I am nearing bed-time, and will have to analyze these tomorrow.

Ernie

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Answer 10

Oct 26, 2006 6:48 AM in response to Ernie Stamper

After I forwarded some of my emails with Microsoft Word attachments to Ernie with full header info, he was able to narrow the problem down to attachments from Mac to PC WITHOUT a file extension (i.e. .doc). After I ran several tests under different conditions as suggested by Ernie, the following conclusions seem apparent:

When sending Word document attachment from Mac to PC:
1) Always make sure the extension .doc is present in the Sent document
2) If .doc is not present for some reason, the proper extension will still
be appended in the received PC Outlook Express if:
a. Plain Text is used and/or Windows Friendly box is checked
b. Rich Text is used but Windows Friendly IS NOT checked
3) Combination of missing .doc extension , Rich Text, and Windows
Friendly causes the attachment to be appended with .dat in the PC,
and will not open in Word. [ This is the original problem we started
with.]

This leaves me with the knowledge of what to set to prevent this problem. I leave to Ernie and other experts to work out the WHY.

Thanks again to Ernie for spending so much time to resolve this problem.

Charles

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Answer 11

Oct 26, 2006 11:13 AM in response to Charles Wyatt

Hi All,

I see the same problem, and did a few test :

1) Even with .doc extension is shown, the file still being converted to .dat

2) I don't think it has something to do with which SMTP server, as I tried a few servers, the results are the same.

3) I tried using the same server's webmail, the problem won't happen. So I believe the problem is from Mail.

4) I also tried playing with combination of Rich Text/Plain Text, Window Friendly, result are the same for the same file.

5) I have also tried old file, new file, new msg, forwarded msg, results are the same.

6) Not only converted to .dat, but some of the file names are trancated to single word plus .dat

7) I tried rename the problem file before sending, basically to shorter name, then some will be ok. I believe it has to do with the length of the file name, but I haven't spend time to test as to how many alphabat is the critical point.

I hope others can help find out more on this.

Best regards.
Mac Beachboy

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Answer 12

Nov 29, 2006 4:02 PM in response to Mac Beachboy

having the same problem here.

just switched to a core 2 duo macbook pro about a month ago and have been having trouble with any and all text-based attachments (Word documents, Excel files). I have been receiving winmail.dat attachments and this was an easy fix on the mac using OMiC for Mac OS X Mail.

However, Mac OS X Mail is still sending attachments to my colleagues (using Outlook)) as .dat attachments. There is no change in the name of the file, just the extension is changed to .dat. These files can be opened through renaming the file, or browsing within the program on windows (just that its annoying to do so and should be automatic).

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Answer 13

Nov 30, 2006 8:26 AM in response to tyson Liebrecht

After many test, I am able to conclude this bug, that :

If file name is long, this will happen.

If you rename it to shorter name, it won't happen anymore. (However, I didn't count how long is limit tho. The longest I have tried and still work is 55 characters excluding the .doc)

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Answer 14

Dec 7, 2006 5:56 AM in response to tyson Liebrecht

Hello,

I have not tested this with an Intel Mac, but with Word (and Office) on Macs, there has generally been a 27 character limit (including extension). Although the MacIntosh version can create the file, subsequent reopening and Saves will mess with it. Also, you can receive, and initially open a document with a longer name that you have been sent, but altering and saving will again mess with it.

I have not heard of this limitation being fixed by MS.

Ernie

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