I done an application using Power Point Interop library and it works well but if I copy it from DEBUG folder to another place, when I start it it gives me an error like: "Application has encountered a problem and needs to be close. We are sorry for the inconvenience". It just cannot start. I tried to copy the Microsoft.Interop.PowerPoint DLL in the same folder but does not work.... why? Build issue? Can somebody help please? :D