IObjectCopy copier = new ObjectCopyClass(); var newLayer = copier.Copy(oldLayer) as ILayer; myMap.AddLayer(newLayer); // ArcMap?? Bad subtypes renderer after copy. Workaround. newLayer.Name = "name differs from old layer name";
Its a bit late, but it works with ArcObjects.Net 10.4.1 and helped me a lot, so thanks 😉