Consider the following scenario. You move a site collection from one content database to another content database in Microsoft SharePoint Foundation 2010. You perform a search. In this scenario, the site collection that was moved is missing from the search results.
To resolve this issue, apply the following hotfix packages:
2479788 Description of the SharePoint Foundation 2010 hotfix package (sts-x-none.msp): February 22, 2011
2479795 Description of the SharePoint Server 2010 hotfix package (osrchwfe-x-none.msp): February 22, 2011