.dat Extension: Opening Of ?

Discussion in 'Computer Support' started by Bob, Jul 27, 2010.

  1. Bob

    Bob Guest


    I received an Attachment in an e-mail with a .dat extension.

    Nothing I seem to have will open it.

    What can I use, please ?
    Running W7.

    Bob, Jul 27, 2010
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  2. Bob

    Bert Hyman Guest

    In Bob
    Ask the person who sent it to you.
    Bert Hyman, Jul 27, 2010
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  3. Bob

    richard Guest

    If it's a small size file try notepad.
    Generally these are standard text files.
    richard, Jul 27, 2010
  4. Bob

    Mike Easter Guest

    Is this email from someone you know or is it from an unknown source?

    Is the name of the attachment winmail.dat or something else .dat?
    Win7 does not come with a mail user agent and you failed to mention
    which agent you have installed - perhaps it is Windows Live Mail or
    perhaps you are using the Tbird 3.0.3 for mail that you posted here with.

    The .dat extension is 'arbitrary' and is not associated with a
    particular application, indicating that the person who sent it to you
    doesn't know very much about interacting with others by email.

    The most notorious group of people who don't know much about interacting
    with others by email are those who use MS specific/proprietary apps such
    as OL Outlook.

    It would/might help if you look at the attachment structure. You can do
    this with WLM by using ctrl-F3 and you can do it with Tbird by using ctrl-U

    If the problem is an OL attachment there are instructions you should
    give the sender to quit doing that. If the problem is some other kind
    of attachment, you need to get back with us about the attachment
    structure seen in the message source.

    You can also save the .dat file to disk and examine its front part with
    a hex viewer.
    Mike Easter, Jul 27, 2010
  5. Bob

    richard Guest

    No moron. He said ".dat" as in "DATA".
    FYI bin does not necessarily mean binary either. You have heard of "Recycle
    Bin"? "Bin" simple means a receptacle. Loosely.
    richard, Jul 27, 2010
  6. Bob

    Jordon Guest

    Dollars to doughnuts the person that sent it to you is
    using Outlook (not Express). It's a problem with Outlook
    that M$ refuses to do anything about and it's been around
    for years. Google...

    outlook .dat

    and you'll find a ton of information. There are some
    free Outlook .dat converters out there. Or you can
    instruct your friend on how to prevent it in the

    Oh, and never listen to richard.
    Jordon, Jul 27, 2010
  7. Bob

    John Holmes Guest

    Mike Easter "contributed" in 24hoursupport.helpdesk:
    Mike, the OP doesn't even know how to open an email with some .dat
    extension. Now how would (s)he know what a hex viewer is all about, eh?
    John Holmes, Jul 27, 2010
  8. Bob

    Aardvark Guest

    No, dat.as in data.
    Aardvark, Jul 28, 2010
  9. Bob

    PeeCee Guest


    The sender screwed up.
    Just ask them to resend in the format they 'meant' to send it as.

    PeeCee, Jul 28, 2010
  10. Bob

    VanguardLH Guest

    RTF (Rich-Text Format) is often used to describe one of Microsoft's mode
    for formatting e-mails. RTF actually includes HTML but usually means to
    refer to Microsoft's TNEF format. The only e-mail client that
    understands RTF (TNEF) is Microsoft's Outlook e-mail program. Not even
    Microsoft's Outlook Express, a completely separate e-mail client that
    they obtained elsewhere when it used to be called Internet Mail and News
    (hence the msimn.exe filename), can understand RTF used in Outlook. All
    other e-mail clients - you never bothered to say what YOU use - will
    show a winmail.dat attachment (except for Outlook Express which won't
    show the attachment). The winmail.dat attachment contains all the
    formatting specified in the RTF document.

    RTF/TNEF should only be used within a closed community of Outlook users,
    like employees at the same company. It should also be used only when
    Exchange is the only mail server involved since corruption can occur if
    using non-Exchange servers. This type of environment works at a
    company, not when sending e-mails across the Internet. Plain-text or
    HTML should be used when sending e-mails to Internet recipients. In
    fact, a user configurable option in Outlook says to convert RTF e-mails
    into HTML e-mails if sending to an Internet recipient.

    Tell the sender to resend their RTF e-mail but use plain-text or HTML
    format. Windows 7 doesn't come with any e-mail client. You never
    bothered to tell use what e-mail client you chose to install. If you
    didn't install Outlook then you either need to get the e-mail sent in
    plain-text or HTML format, or you'll have to endure installing 3rd party
    software that can view the winmail.dat file, like Winmail Opener.

    VanguardLH, Jul 28, 2010
  11. Bob

    chuckcar Guest

    In which case it wouldn't *be* a small file.

    No, it doen't have *any* extension, which is worse. I find your last
    remark to be the least likely of all the above frankly.
    chuckcar, Jul 28, 2010
  12. Bob

    chuckcar Guest

    You *can't*. DAT is not a defined extension in windows. It *can* be
    digital audio tape, some kind of user defined data file, a file from a
    database program, Even an archaic format of movie, but unless you have
    something specifially installed for the general uses of those above, it
    simply won't be used at all. It's far too often used as a file that's
    read and *not* to open with any sort of editor.
    chuckcar, Jul 28, 2010
  13. Bob

    chuckcar Guest

    Wrong. Microsoft windows *knows* what it is without *anything* else
    installed - it has to for preview and file properties to work. Any
    version of Windows with nothing else installed won't even do that
    for a *.dat file.
    chuckcar, Jul 28, 2010
  14. Bob

    John Holmes Guest

    chuckcar "contributed" in 24hoursupport.helpdesk:
    FYI, anyone with some knowledge can open any file with a HEX editor to
    see what kind of file (s)he's dealing with. Obviously, the OP doesn't
    know how to handle a simple .dat file so telling him to use a HEX editor
    would be far beyond the OP's skills, right?
    John Holmes, Jul 28, 2010
  15. Bob

    joevan Guest

    Or maybe José Feliciano. I heard they watched each other on TV years
    joevan, Jul 29, 2010
  16. Bob

    chuckcar Guest

    Although a copy of a dump of the first hundred bytes with debug might be
    doable. The fact is that someone has a .dat means nothing all by itself.
    That is the problem right now: What *is* the file for.
    chuckcar, Jul 29, 2010
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