After installing FCS Express 5 or 6 and running the application for the first time, you may be presented with two messages regarding .Fey Extension Registration.
These messages are confirmation that files with the extensions .FEY or .FE_LAUNCH are native to FCS Express. As a result, when you try to open a file with either of these extensions, Windows will automatically associate these file extensions with FCS Express and launch FCS Express when trying to open files with these extensions.
Simply, click the checkbox for Do not attempt to register the extension again and click on Yes. FCS Express will launch normally when opening FCS Express layouts and you will no longer be presented with the question.