We installed SP2 for SQL Server 2008 R2 (was on SP1 CU3) in an existing Dev/Test environment to test. We are using SharePoint Integrated mode setup (SP 2010 SP1 CU Aug 2012). The following day the stored credentials that we had saved for the shared data sources was no longer valid (the user name was missing). I am assuming that because of this all of the references to these were removed from the reports and shared datasets. Something must be modifying the stored credentials or removing them from the data sources in nightly maintenance. Along with this the shared data source is disabled.