When aCommunicator 2007 R2 or Lync 2010 client is unable to synchronize address book files,manually deleting the Galcontacts.db and Galcontacts.idx helps resolve the problem. However, manually deleting the files is not ascalable solution foranorganization that has more than 25users. This article describes a script that can help you automaticallydeleteGalcontacts.db and Galcontacts.idx files.
Read more at source: http://blogs.technet.com/b/nexthop/archive/2011/12/22/script-to-delete-galcontacts-db-for-multiple-microsoft-office-communicator-2007-r2-and-lync-2010-users.aspx
Cheers,
Anderson Patricio
http://blogs.msexchange.org/patricio
Twitter: @apatricio