If you have an excel spreadsheet that uses PowerPivot (SQL Server 2012) and Office 2010, you have to open the file in a specific way to keep using PowerPivot. Basically, double clicking the file to open it will result in a missing PowerPivot tab. This can be resolved by opening Excel and dragging the file in, or opening through Excel. Double Clicking the file to open should be a supported path.
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