The Outlook Address Book is guarded programmatically. This helps to prevent another program from automatically accessing your Address Book or Contacts list or from sending messages on your behalf without your permission. It is very useful to allow some programs (like Microsoft ActiveSync® or Palm Desktop) to access your contact information so that you can synchronize your personal digital assistant (PDA). However, a virus or other malicious program file can use the same functionality to propagate itself. If a program attempts to access your Address Book, a warning appears on screen.

This message appears if a program tries to access your Address Book. In general, you cannot prevent this caution from appearing. However, check with your synchronization software vendor to see if recent updates to the vendor's software include interacting with Outlook in a trusted manner. This message is not displayed when Outlook interacts with trusted synchronization software.

• Unless you clicked a command or started a program that is expected to interact with Outlook Address Book information or if you are just not sure, click No.
• If you clicked a command or started a program that is expected to interact with Outlook Address Book information, select the Allow access for check box, and then specify the amount of time you grant access for.