Scripts won't attach

So, this is probably one of those things that gets posted once a month by newbies, but my scripts won’t attach. It keeps giving me an error whenever I try to attach a script–and we’re talking Unity’s stock scripts like the character controller–to a prefab or a gameobject, saying that the script hasn’t finished compiling yet and that I should wait for it to finish. I KNOW it’s not in the middle of compiling anything. What’s going on? Is there some way I can force it to compile so I can get on with working on stuff?

Are you certain there are no errors with the scripts in question? You haven’t modified them at all? Which scripts are you trying to use in particular?