The others have given some possible causes of the problem.
If the attachment name is WINMAIL.DAT, then the issue is the Outlook
Another possible cause is that the sender is using the Break apart
option and the message is not getting put back together automatically.
If the sender is using Outlook Express, Vista Windows Mail or Windows
Live Mail have then look at Tools (ALT+T), Accounts, Mail, Properties,
Still another issue is if the sender is using a Mac.
For some additional information, see:
Decoding Internet Attachments - A Tutorial http://TechHelp.Santovec.us/decode.htm
Mike - http://TechHelp.Santovec.us
"guybc" <guybc@newsgroup> wrote in message
> I receive some .doc files as attachments that were made in Word, but
> in my inbox as .dat and cannot be read, even if opened in Word.
> Some files generated in Word and sent as .doc file attachments arrive
> their destination unreadable.
> These files are failrly large - 4-6 Mb.
> This never happened with XP.
> I'm using Windows Security. Windows 7 Pro. 64 bit.
> Can anyone suggest an answer to this problem?