Consider the following scenario:
In this scenario, you receive the following error message:
Microsoft.ReportingServices.Diagnostics.Utilities.SharePointException: Report Server has encountered a SharePoint error. ---> Microsoft.SharePoint.SPException: The specified user <user name> could not be found.
Service pack information for SQL Server 2008 R2
To resolve this problem, obtain the latest service pack for SQL Server 2008 R2. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
How to obtain the latest service pack for SQL Server 2008 R2
Browsing directly to the report server is not supported in SSRS 2008 R2. Therefore, do not browse to the report server directly. Instead, use the report server proxy on the SharePoint Web site that uses the appropriate authentication provider. The following is an example of a URL that lets you access the report server by using the report server proxy on the SharePoint Web site:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
This problem was first corrected in SQL Server 2008 R2 Service Pack 1.