OL98: Why Outlook Displays a Security Warning Opening an Item (182376)

MORE INFORMATION

Outlook always prompts you before opening an item that contains Visual Basic Scripting Edition (VBScript) code if the item is from an unknown source. Outlook bases the decision to display or not display a warning on the item's form design.

• If the form that the item is based on is registered in the Exchange forms registries (organizational forms, folder, or personal forms), Outlook considers the form safe, and no warning appears. The author of the form had the appropriate privileges to publish the form, so the form is considered trusted.
• If the form definition is carried with the item, the author modified the form and sent it, without publishing it in one of the form registries, Outlook considers the form unsafe, and the user receives a warning when opening the item.
  
  NOTE: It is possible that the form definition is being saved with an item even though a forms designer did not turn on the "Send form definition with item" property on the form. For more information about how form definitions can be unexpectedly saved with an item, please see the following article in the Microsoft Knowledge Base:

  181266 OL98: Working with Form Definitions and One-Off Forms

This methodology ensures that unsafe VBScript cannot run on a your computer without your explicit approval.

• If a form is correctly published and some changes have been made before the form is sent. This usually happens when the form is called programmatically in another custom form. And some custom properties are added before the called form is sent.