You cannot automatically sign in to Communicator 2005 on a Windows Vista-based computer when the "Automatically open the main window when Communicator starts" check box is not selected in Communicator 2005

On a Windows Vista-based computer, you click to clear the Automatically open the main window when Communicator starts check box in Microsoft Office Communicator 2005. Then, when you log on to Windows Vista, you may be unable to automatically sign in to Communicator 2005. However, you can automatically sign in to Communicator 2005 when you log on to Windows Vista if the Automatically open the main window when Communicator starts check box is selected in Communicator 2005.

Note To find the Automatically open the main window when Communicator starts check box in Communicator 2005, click Options on the Actions menu, and then click the General tab.

This problem occurs if there is an issue with the network detection algorithm.

How to obtain the hotfix

This issue is fixed in the Communicator 2005 Hotfix Package that is dated June 29, 2007. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.