I have a PowerPivot solution built in Excel 2013, which I have deployed to a SharePoint 2013 single server farm, which is also running SSIS/SSRS/SSAS 2014. 

I have configured data refresh jobs, which are running successfully, according to the PP management dashboard in SP.

I attempted to open the file from the document store in SP directly, and when I went to make modifications to the data model, tom horror I was greeted with "We couldn't load the data model. This may be because the Data Model in this workbook is damaged". Further clicks on the OK button provide a bit more context.

============================
Error Message:
============================

Object reference not set to an instance of an object.

============================
Call Stack:
============================

   at Microsoft.Office.PowerPivot.ExcelAddIn.InProcServer.CannotUpgrade(GeminiWorkbook geminiWb, WorkbookConnectionwbConn, String& message)
   at Microsoft.Office.PowerPivot.ExcelAddIn.InProcServer.LoadSandboxAfterConnection(String errorCache)
   at Microsoft.Office.PowerPivot.ExcelAddIn.InProcServer.LoadSafeSandboxAfterConnection(String errorCache)
   at Microsoft.Office.PowerPivot.ExcelAddIn.InProcServer.LoadOLEDBConnection(Boolean raiseCompleteEvent, String errorCache)

============================

Unfortunately I've seen this before, and unfortunately it's been fatal. Fortunately since the last time I've seen this, I've become a bit more adventurous. Here's what I've done, and I'd really appreciate some community help to take this the last few inches to a conclusion. Maybe some help from the Office team, since you're 15 minutes from my office :)

Using Visual Studio, I can see that the data model itself is intact. I was able to start a new solution using the supposed corrupt file as a starting point. That's a good thing, but I don't know how to recycle it into a new Excel file so I don't lose all of the work I've put into it.

Using SQL Management Studio, using SELECT * FROM [PowerPivotServiceApplication1_endpoint].[dbo].[Versions] I can see that the reported Version is 12.0.1.0.

Also using SQL Management Studio, I can see that the server version for the server used for PowerPivot is 12.0.2000. I wonder if this version disparity is causing Excel to want to upgrade my file, and this is triggering a larger issue?

I seem to recall seeing somewhere that PP for SP2010 was not supported in a single server farm. I don't know if the same is true for SP2013, and frankly don't care (at this point, since all I am after right now is my data model back). I'm wondering if the SP data refresh jobs are causing this, and the null exception is maybe a pointer to a second server in the "farm" that doesn't exist.

Lastly, I am more than willing to make changes to the underlying XML files that make up the XLSX file. If there's a way to know where the null value is being referenced (if possible) and make it go away, that would be stellar. 

Any help is greatly appreciated. Like I said, I'm very willing to go down deep rabbit holes, sit with devs, whatever it takes.

Thanks 

Any help on this is greatly appreciated. I'm 

Torben,

Is this still an issue?

Thank you!

Yes, it's still an issue. Anything you can do to help?

I asked for some more help. Thanks!

Using Visual Studio BIDS/SDT?

Hi Ed, 

Sorry but I don't understand what your frame of reference is. Are you asking if I'm using BIDS or SDT and that is causing the problem? Or are you asking whether I'm using either of those two tools and that will help with a solution?

I am using SSMS and SDT/VS2012 if that's helpful at all.

Thanks. We couldn't find anyone who knew this.

Have you figure it out any?

Thanks!

Ed I haven't figured it out - it continues to be an issue from what I can tell. The only way to save the data model is to suck it into SSAS but the problem is you can't stuff it back into Excel as a PP model. 

We're still looking for an answer for this.

I'm trying again. Thanks!

I submitted a request to get help on this. Thanks!

Torben, is this still an issue? I haven't been having any luck finding an SME for this one.

Thanks!

Yup, still an issue. Got more workbooks that have been similarly affected

Here's one thought...

Because the error occurs with more workbooks, the reason is probably external to the files, model etc. but common to it, such as permissions or user specific policies on his workstation or servers involved, This Microsoft Excel Support Team Blog article is an example of a cause for a similar seemingly scary error message:

http://blogs.technet.com/b/the_microsoft_excel_support_team_blog/archive/2013/08/27/powerpivot-for-excel-2013-error-when-opening-the-manage-window-quot-we-couldn-t-load-the-data-model-this-may-be-because-the-data-model-in-this-workgroup-is-damaged-quot.aspx 

I considered that Ed but it's not the case. There's an another thing that occurs when you implement workbook security with similar results but is not related to this. 

Anybody else have a suggestion for Torben? =^)

Torben, have you been able to try anything else for this?

Thanks!