I normally have no trouble editing components or making them unique but today, when I right click on a component, almost all of the options, including the edit and make unique are gray. I read that you need more than one instance of a component to make it unique and I definitely do have two instances of the same component. I even created a third one just to be sure.
This may be a general known contextual menu issue, and not to do with make unique in particular. Does the problem go away if you reopen SketchUp?
See other topics about the general issue. Here for example:
Yes it does! Thank you very much Colin. I should have tried that myself! I just assumed it was my fault.