Importing Excel Charts from Excel to PowerPoint causes `RPC_E_SERVERFAULT` on some machines

This is an irritating one. I have created a method to copy all Excel charts in a workbook to PowerPoint slides.

public int ImportExcelChartsFromWorkbookToSlides(int startingSlideIndex, string workbookPath, string[] slideTitles, int chartPosTop, int chartPosLeft = 10, int titleWidth = 680, int titleHeight = 20, int titlePosTop = 90, int titlePosLeft = 20, int titleFontSize = 18)
{
    int slideIndex = startingSlideIndex;
    int titleIndex = 0;
    EXCL.Application objExclApp = new EXCL.Application();
    EXCL.Workbook objWorkbook = objExclApp.Workbooks.Open(workbookPath, Editable: false);
    foreach (EXCL.Worksheet objSheet in objWorkbook.Worksheets)
    {
        foreach (EXCL.ChartObject objChart in objSheet.ChartObjects())
        {
            AddBlankSlide(slideIndex);
            AddTextBox(titleWidth.ToString(), titleHeight.ToString(), titlePosTop.ToString(), titlePosLeft.ToString());
            AddTextBoxParagraph(slideTitles[titleIndex], fontSize: titleFontSize.ToString(), useThemeFont: true);

            // Copy Chart from Sheet to Slide
            objChart.CopyPicture();

            PPT.ShapeRange objShapeRange = objSlide.Shapes.Paste();

            objShapeRange.Left = chartPosLeft;
            objShapeRange.Top = chartPosTop;

            slideIndex++;
            titleIndex++;

            Marshal.ReleaseComObject(objChart);
            Marshal.ReleaseComObject(objShapeRange);
        }
        Marshal.ReleaseComObject(objSheet);
    }
    objWorkbook.Close();
    objExclApp.Quit();
    Marshal.ReleaseComObject(objWorkbook);
    Marshal.ReleaseComObject(objExclApp);
    objWorkbook = null;
    objExclApp = null;
    return slideIndex;
}

As is usually the case, this works perfectly on my machine, but some users are reporting an RPC_E_SERVERFAULT from this method. (HRESULT: 0x80010105)

Somewhere in this method is causing the issue. Either that or it is some issue with different installs of office, a memory issue or an add-in causing the problem. I have tried this on a couple of other machines but they all still work.

RPC_E_SERVERFAULT is nasty and hard to diagnose. You get this error when Excel crashed. Without any details, this kind of crash is supposed to be reported by the app itself. Which is not happening, worse is that Excel keeps running even though something rather bad happened. You can't make any real headway on such a mishap until you get your hands on a machine that exhibits this problem.

It is however not that hard to find fellow victims, just Google "chartobject rpc_e_serverfault". They all look just like yours. Minus a good solution.

I have a fairly good theory for the underlying problem. At issue is that Microsoft has managed to keep the Office interop interfaces compatible for 19 years already. Rather a stunning achievement, and something that everybody takes for granted even though there is nothing trivial about it, but it has been running out of gas. Charts are noteworthy as a common troublemaker.

Have a look-see at the definition of the IChartObject interface. Flip back-and-forth between the Office 2013 and 2003 definitions. And note the mysterious _Copy() method addition. Seemingly entirely unnecessary since there already is a Copy() method. And undocumented.

That is a problem. If you look at the interface definition with GoTo Definition in VS then note that it is the second method in the interface table. That is a big, big problem. It breaks binary compatibility of the interface.

Consequences are dire, if you used the interop library for Office 2013 to build your program and the user has Office 2003 on his machine (or 2007, can't tell) then the CopyPicture() call in your program calls the completely wrong implementation method. Presumably Cut(), a method that takes no arguments. This is very bad, if the method itself doesn't implode then the stack imbalance can cause all kinds of havoc. RPC_E_SERVERFAULT is the expected outcome.

So a workable theory is that this bombs on machines that have an old Office version. Little you can do about it on your end, other than building another version of your program that uses the 2003 interop libraries and instructing IT staff to be careful when they distribute it. Upgrading the machine is by far the simple workaround.