I know with Blueprints files if you try to migrate those into a different project (not a blank project) it will cause non access errors and break the blueprint code in the other project cause nodes to stop functioning, or the code may work but come up with a page full of non access errors straight after playing. You can migrate the project assets over but not the blueprints or the widgets. So if I want the blueprints from one project over into another, I have to hand code them in, I can’t just move the blueprint files or widgets over with copy or migrate because it causes conflicts with the referencing if the other project is using also the same name variables.