Hello. I have a forms application in C# and Visual Studio. This app interacts with Excel and is working fine. I installed the executable and the configuration file in another computer and when the app calls excel I received a message stating that a library was not registered. The error message says that it's not possible to convert a COM object type 'System.___ComObjet' into the interface 'Microsoft.Office.Interop.ExcelApplication'. My Visual Studio is Community 2019. Does anyone know what to do to correct it? Which DLL should be copied too to correct it? Or which files should be copied too?