PowerPivot Scheduled Data Refresh - Call to Excel Services Returned an error.

I have encountered the error "Call to Excel Services returned an error" when performing a Scheduled Data Refresh.

This is a rather generic error message.  However, we have seen several cases where the Scheduled Data Refresh fails because of Unsupported Features in the workbook. 

We have a tool that you can use to remove these Unsupported Features.

Excel Services Compatibility Checker Download Page

http://blogs.msdn.com/b/cumgranosalis/archive/2007/06/29/excel-services-compatibility-checker-download-page.aspx

First install the "Excel Services Compatibility Checker Add-In".  As you can see a tab called "Excel Services" will appear in the ribbon (may need to restart Excel).  Now you can remove the Unsupported Features by choosing "Quick Fix".  I do suggest creating a copy (back up) of the workbook.  After you have removed the Unsupported Features, republish to the PowerPivot Gallery and run a Scheduled Data Refresh.

Excel Services Compatibility Checker Add in - Beta

http://blogs.msdn.com/b/cumgranosalis/archive/2007/06/29/excel-services-compatibility-checker-addin-beta.aspx

Other Resources:

Differences between using a workbook in Excel and Excel Services

http://office.microsoft.com/en-us/excel-help/differences-between-using-a-workbook-in-excel-and-excel-services-HA010021716.aspx

Excel Services part 12: Unsupported features

http://blogs.office.com/b/microsoft-excel/archive/2005/12/01/excel-services-part-12-unsupported-features.aspx

Excel Services in SharePoint 2010 Feature Support

http://blogs.msdn.com/b/excel/archive/2009/11/19/excel-services-in-sharepoint-2010-feature-support.aspx

  Edit a workbook that contains features unsupported by Excel Web App

http://office.microsoft.com/en-us/web-apps-help/edit-a-workbook-that-contains-features-unsupported-by-excel-web-app-HA102540964.aspx

Again, this is somewhat of a generic message, so this may or may not resolve your issue, but it is definitely worth testing.