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:
    [HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences]
    “DisableTNEF”=dword:00000001
  • 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.

The Trim command should be enabled by default on Windows 7, but if you want to check to make sure do this:

Open Command Prompt, run the following command

Command prompt > fsutil behavior query disabledeletenotify

DisableDeleteNotify = 1 (Windows TRIM commands are disabled)
DisableDeleteNotify = 0 (Windows TRIM commands are enabled)

http://support.microsoft.com/kb/2360509

Step 4: Rebuild the database

  1. Quit all applications.
  2. Hold down the Option key on the keyboard, and then start Outlook 2011.

    Note You can also browse to the Database Utility by opening the Application folder and then opening the Microsoft Office 2011 folder. Open the Office folder, and then double-click Microsoft Database Utility.app.

  3. In the Database Utility window, select the database that you want to maintain, and then click Rebuild.
  4. The Rebuilding Main Identify window will open and show the progress. When the operation is completed, you will receive the message “Your database was rebuilt successfully.”
  5. Click Done.
Select an identity

Start Outlook and see whether the problem is resolved. If the problem is not resolved, go to the next step.

Step 5: Create a new identity

If you are using Outlook in more than one capacity, such as at home and at work, Outlook may be configured to have multiple identities. Each identity stores separate sets of e-mail, address books, tasks, calendars, account settings, and more.

If Outlook has multiple identities, one of the identities might be damaged. Try to use a different identity to determine whether this is the problem. If an identity is damaged, you must create a new identity to resolve this problem.

To create a new identity, follow these steps:

  1. Quit all applications.
  2. Hold down the Option key on the keyboard, and then click the Outlook icon in the dock. The Microsoft Database Utility will open.

    Note You can also access the Microsoft Database Utility by opening the Application folder and then opening the Microsoft Office 2011 folder. Open the Office folder, and then double-click Microsoft Database Utility.app.

  3. Click the plus [+] sign to add a new identity, and then type a name for the new identity. For example, type New identity.
    Create a new identity

The issue may stop temporarily if an Administrator logs into the Hyper-V host and runs the following command:

gpupdate /force
This issue occurs because the NT Virtual Machine\Virtual Machines special identity does not have the Log on as a Service right on the Hyper-V host computer. Usually, the Virtual Machine Management Service (VMMS) replaces this user permission at every Group Policy refresh to ensure it is always present. However, you may notice that Group Policy refresh does not function correctly in certain situations.