• Close Outlook
  • Check that HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Security registry key exists. If not follow these steps:
    • Go to: HKEY_CURRENT_USER\Software\Microsoft
    • Click the Edit menu, click New, and then click Key. Type Office, and then press ENTER.
    • Click the Edit menu, click New, and then click Key. Type 11.0, and then press ENTER. Note This is the correct name if you are using Outlook 2003. If you are using Outlook 2000 or Outlook 2002, you will have to type "9.0" or "10.0", respectively.
    • Click the Edit menu, click New, and then click Key. Type Outlook, and then press ENTER.
    • Click the Edit menu, click New, and then click Key. Type Security, and then press ENTER.
  • Click the Edit menu, click New, and then click String Value. Name it Level1Remove and press ENTER.
  • Right-click the new string value name, and then click Modify.
  • Type the file name extension of the file type that you want to open in Outlook. For example: .exe and then click OK
  • To specify multiple file types, use the following format: .exe;.com
  • Quit Registry Editor
  • No restart needed, just restart Outlook