Symptoms
Assume that you use Microsoft SQL Server 2012 or SQL Server 2014 PowerPivot Add-in for Excel 2010, and you have saved the password that connects to the back-end data source of the PowerPivot model. When you try to configure scheduled data refresh for the PowerPivot workbook in SharePoint 2013, the "Use the credentials contained in the workbook" option does not work, and the refresh of Excel 2010 workbooks fails.
Resolution
The issue was first fixed in the following cumulative update of SQL Server.
Cumulative Update 4 for SQL Server 2014 /en-us/help/2999197
Cumulative Update 2 for SQL Server 2012 SP2 /en-us/help/2983175
Cumulative Update 11 for SQL Server 2012 SP1 /en-us/help/2975396
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
