Reset the content index in Search Server 2010

You should reset the content index only when you plan to crawl content after you have created a new set of content sources. When you reset the content index, all search results are immediately removed. After you reset the content index, you must perform a full crawl to create a new content index so that a current results set is available to users.
Use the following procedure to reset the content index.

To reset the content index

1. Verify that the user account that is performing this procedure is a service application administrator for the Search service application for which you want to reset the content index.
2. On the SharePoint Central Administration home page, in the Application Management section, click Manage service applications.
3. On the Manage Search Applications page, click the Search service application for which you want to reset the content index.
4. On the Search Service Application: Search Administration page, in the Quick Launch, in the Crawling section, click Index Reset.
5. On the Search Service Application: Index Reset page, verify that the Deactivate search alerts during reset check box is checked, and then click Reset Now.
6. In the confirmation dialog box that appears, click OK to confirm the content index reset.
   The Search Service Application: Search Administration page opens and the System Status is displayed.
7. Perform a full crawl.