Hi All, I am thinking why sometime we need to rebuild the index? What is the reason to make it corrupt? Previous, when user complain cannot search , I will rebuild the index. before Easter I ran test-exchangesearch, some database was fail so we plan to rebuild the index in coming weekend. but now I run the test-exchange again and It works now, But I didnt do anything? Can someone explain more, or Actually even I dont rebuild the Index Catalog , it will auto rebuild?? ThanKS