KB Article: http://support.microsoft.com/kb/2665724
Consider the following scenario:
- You use a smart card to log on to a computer.
- You sign in to Microsoft Office Communicator 2007.
- You lock the computer, and then you remove the smart card.
- You insert the smart card and unlock the computer after more than 10 hours.
In this scenario, Office Communicator 2007 disconnects from the server. Additionally, you receive a message that asks you to type your credentials.