Article ID: 2598293 - View products that this article applies to.
Assume that you create a user account that has permissions to view items in a Microsoft SharePoint Foundation 2010 document library. You change the name of the user account, and then you perform a search for items in the document library by using the user account. In this situation, no items are returned.
This issue occurs if one of the following conditions is true:
To resolve this issue, apply the following update:
(http://support.microsoft.com/kb/2598304/ )Description of the SharePoint Foundation 2010 hotfix package (Wss-x-none.msp): April 24, 2012
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.