Strange appearance of winmail.dat


  • Dear all,

    Can you help me with following issue.

    A Customer of mine has a hosted exchange account called

    There are two secretaries, Anne and Natacha. Each have a plain email account at their internet host called and

    I have installed on the pc for Anne (Windows 7 / office 2010) in Outlook the exchange account and the account

    On the pc for Natacha I installed in Outlook the same exchange account and

    When Anne sends, via the calendar of and via her own anne account, calendar meeting invitations to a third person called Daphné, when Daphné receives the invitations on her IPhone, she can read the content of both OK.

    When Natacha sends analogue invitation from and , Daphné can read on her IPhone the invitation send from but the invitation from secretary exchange account she can't read. The mail has an attachement winmail.dat. I have check that all mail are converted to HTML in Outlook and can access the exchange server as it is hosted. The people from the hosting (OVH) say the exchange is OK as it works for Anne. But all Outlook options are the same for all accounts, so why does Natacha have problems with the exchange account and not with here own account.   Please help me on this issue! Thanks for any help, Henri

    Wednesday, February 17, 2016 8:43 PM


All replies

  • Answered your duplicate post in the General Discussion forum.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!

    Wednesday, February 17, 2016 11:02 PM
  • Thanks for the answer. It's the first time I hear about it and always worked so far. Even on the PC that gives problem. It only started after a full reinstall of windows and office because corruption of a virus. Considering that you are right, so how do I, on the same PC give the user access to both email accounts?

    Thursday, February 18, 2016 8:13 AM
  • Hi,

    According to your description, I understand the issue only occur on a specific exchange account.

    It may be a corrupted mailbox in the problematic mailbox.

    I suggest you try a mailbox repair job with New-MailboxRepairRequest for test:



    Thursday, February 18, 2016 9:06 AM
  • Both users access the same mailbox

    The Exchange server is hosted so I can't do anything and the people at OVH (the host) I called say there is nothing wrong as one of the connected secretaries has no problem.

    Otherwise I can delete the .OST file on the local PC from the secretary that has issues?

    Thursday, February 18, 2016 10:00 AM
  • Hi,

    Sorry for misunderstanding your words.

    I have found the following article for your reference, please take the methods in the article for test :

    Hope it's helpful to you.



    Monday, February 22, 2016 9:26 AM