I have a .Net Windows forms program written many years ago, and I don't remember under which version of Visual Studio. That program references the Excel interop. My customer has it installed on a network drive. To my surprise, the installation folder does not have the interop DLL. I would have thought that years ago when I delivered the program I would have put that there.
Anyhow, they are moving to Win10 machines, still running this with a shortcut to a network drive. One Win10 machine doesn't work, saying the DLL is not registered, while other Win10 machines work just fine.
I don't know what I'm looking for to try to resolve this.