When using Excel Services to display data from an Analysis Services cube, the following error might occur when the cube structure changes.
Web part page error
If the Excel spreadsheet is displayed as a web part, the following error will appear in the web part page:
Text: Error. Web Part Error: An error occurred while setting the value of this property: Microsoft.Office.Excel.WebUI.ExcelWebRenderer:WorkbookUri – Exception has been thrown by the target of an invocation.
Edit Web part error message
Text: Cannot save all of the property settings for this Web Part. An error has occurred
An item with the same key has already been added.
The error comes in scenarios such as: after cube changes such as when a dimension has been deleted, and this dimension is used as a page filter in the Excel pivot table and the page filter was a named item and the named item was exposed as a parameter to Excel Services when saved into SharePoint. If the Excel file is updated with the new metadata from the cube but the named items is not, the error message appears.
The solution is to update the Excel file with the new metadata from the cube and also update the named items used as parameters so that they correspond to the relevant cells in the filters area.