Upgrading from Power Pivot workbooks to SSAS Tabular models is usually a pretty seamless process.  This is part of the beauty of the relationship between Tabular and Power Pivot.  This allows an Analyst to get started on a project using Power Pivot and when new requirements like row level security are needed IT can upgrade the workbook to Tabular and add the security feature. 

While this generally is a smooth process I often see the same couple error messages pop up for folks that are doing this.  So here’s a couple of the most common problems and how to deal with them. 

Error:  The file chosen does not contain PowerPivot content embedded in it. Choose a valid PowerPivot for Excel file.

Translation:  The version of Excel that you are trying to upgrade is not compatible with the version of SQL Server you are running.  This often happens when you are trying to upgrade an Excel 2013 workbook to SQL Server 2012.  You can narrow this down to the problem because if you attempt to upgrade and Excel 2010 workbook it works without any issue.

Solution:  This problem has been solved with SQL Server 2012 SP1 and Cumulative Update 4.  Install these and you shouldn’t see the issue any more.

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Error: The PowerPivot workbook could not be imported. The service account for the workspace database server does not have permission to read from the PowerPivot workbook.

Translation: The Service Account that is running the SSAS Tabular does not have rights to the folder that the Power Pivot workbook is stored in.  You can find out which account this is by launching the SQL Server Configuration Manager and find the instance name.

Solution:  Grant the Service Account the permissions it needs or move the Power Pivot workbook to a folder that the Service Account does have access to.

If you know the Service Account does indeed have access but still is not able to import with this error then again you likely need to upgrade to SQL Server 2012 SP1.

Summary

As you can see both of these problems can be solved by upgrading to the latest Service Pack.  Remember SSAS Tabular was a new product to SQL Server 2012 and as you may expect with a new product if will go through some growing pains.