"Either there is no default mail client or the current mail client cannot fulfill the messaging request" error message when you send e-mail from third-party program in Outlook"


http://support.microsoft.com/kb/813745


Caused by registry corruption.


  1. Click Start, and then click Run.
  2. In the Open box, type regedit, and then press ENTER.
  3. In Registry Editor, locate the following subkey in the registry:

    HKEY_LOCAL_MACHINE\Software\Clients\Mail\Microsoft Outlook

  4. Select the subkey, and then press DELETE.
  5. Click Yes.
  6. Quit Registry Editor.
  7. Start Outlook.
  8. For Outlook 2000 and Outlook 2002, click the Help menu, and then click Detect and Repair .
    For Outlook 2007, click the Help menu, and then click Office Diagnostics .
    For Office 2010, Click Start, click Control Panel, click Programs and Features, select Microsoft Office 2010 and then click the Change button. Next, click Repair, and then click Continue.
  9. Follow the instructions on the screen to complete the repair.