Revit 2024.2 Add-In Excel "Element Not Found" Error

[jgerads4KMWR]

I have created a simple Revit add-in that automatically fills in the sheet's border information based on information within an excel file. This add-in works fine in Revit 2024.1, but when trying to use it on a machine with 2024.2 installed the following error is shown.

In my code I am using Microsoft.Office.Interop.Excel to interact with Excel. My add-in is a C# Class Library in Visual Studio using .NET Framework 4.8. Any ideas on why this would work with 2024.1 but not 2024.2 would be greatly appreciated!

[RPTHOMAS108]

It is a COM issue to do with how the COM interfaces are registered not Revit API. If you do a quick repair on Excel that will often fix it until the next Windows security update breaks it again. Which version of Excel is it?

Those COM interfaces are so fragile and the problem is always machine specific so impossible to know that if you use COM it will work at destination. "Repair Excel" that is all you can advise to someone using your add-in blaming you for their COM issue.