When I add a custom assembly to SSRS, I got the following error, Request for the permission of type 'System.Data.SqlClient.SqlClientPermission, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed. I checked rssrvpolicy.config and Windows\Microsoft.NET\Framework\v2.0.50727\CONFIG\security.config, The one from security.config is, < SecurityClass Name="SqlClientPermission" Description="System.Data.SqlClient.SqlClientPermission, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> but rssrvpolicy.config shows, < SecurityClass Name="SqlClientPermission" Description="System.Data.SqlClient.SqlClientPermission, System.Data, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> Any idea? Thanks. Rui

Hi Rui, The issue you mentioned occurs due the System.Data.SqlClient.SqlClientPermission is not asserted in the custom code. In order to access data in Microsoft SQL Server tables by using the "System.Data.SQLClient" namespace in a custom assembly, we must add the following code to the custom assembly before we use the "System.Data.SQLClient" namespace: System.Data.SqlClient.SqlClientPermission pSql = new SqlClientPermission(System.Security.Permissions.PermissionState.Unrestricted); pSql.Assert(); For more information, please see: How to grant permissions to a custom assembly that is referenced in a report in Reporting Services: http://support.microsoft.com/kb/842419 If you have any more questions, please feel free to ask. Thanks, Jin Chen Jin Chen - MSFT