A. Outlook 2000 has a bolt-on security "enhancement" that prevents you from opening certain attachment types. Microsoft made this enhancement part of the core Outlook 2002 functionality. However, the company has fortunately provided a way to open certain attachments:

  1. Start regedit.exe.
  2. Go to HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security.
  3. From the Edit menu, select New, String value.
  4. Enter a name of Level1Remove, and press Enter.
  5. Double-click the new value, and enter the extensions you want to allow. For example, entering zip;exe;url unlocks ZIP files, executables, and Internet shortcuts.
  6. Click OK.
  7. Restart Outlook.
Note that you still have to save an attachment to disk before you can open it.

Also note that administrators can prevent users from customizing the blocked attachment list by adding a different registry key as a policy or, in an Exchange Server or HP OpenMail environment, by establishing security overrides in a public security settings folder. The Office XP Resource Kit explains these settings in detail.