We are running Exchange 2007 SP2 with rollup 1 in a SCC cluster on Windows Server 2008. Recently, our search functionality from Outlook just randomly stops working even few days. I have rebuilt the catalogs according to this article: http://technet.microsoft.com/en-us/library/aa995966(EXCHG.80).aspx but that has not helped. The service is running just fine, and I'm not seeing anything that jumps out at me in the event logs. Once I restart the service, search begins working again immediately.