How to fix Outlook and winmail.dat problem

After those regular fixes if problem still occurs

  • Set Contact to “Let Outlook decide the best sending format”.
  • In Options/Mail/Compose Messages in this format set to “HTML”
  • In Options/Mail When Sending Messages in RTF to Internet to “convert to HTML format”
  • Cleared entry from cache, exited outlook, and manually typed entry in
  • Added Key:
  • Disabled Anti-virus e-mail scanning


After above if it still not working, please try the following:

You have to delete the autocomplete cache as RTF settings are saved with the addresses and that may fix the issue.

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