http://blogs.technet.com/b/nexthop/archive/2007/12/27/ocs-2007-continuous-prompts-for-address-book-download.aspxI've now run into this issue a few times where after deploying Office Communications Server 2007 Enterprise Edition that the Office Communicator client is unable to download the address book from the IIS server. Below are some troubleshooting steps thaten-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)