What was (or at least at the time appeared to be) a correct answer to a question of mine is now (possibly due to software changes by Apple) no longer resolves my question. I've already accepted this answer as the correct one. How should I handle the fact that what it suggests no longer works?
Should I un-accept it? Is that sufficient?
Two things work very well.
1) Edit the question to remain historically significant - answer at time. You can edit the answer if needed or just comment that this is no longer true.
1a) If the basic need is still there, re-ask the new question and link the two explaining how the old question isn't the answer since X, Y, and Z have changed.
2) Edit / comment the question to indicate how old answers are not relevant with new X arriving.
So - here are the guiding principles as I see them.
It's really your choice - neither is wrong to choose. The only wrong move is to allow the incorrect content to sit without at least a comment explaining the new circumstances. Again, you don't have to do even that, but from a "how should it be handled" ideal situation - always addressing things that need help is the correct answer.
I would say that if your question and the posted answer remain accurate for some context, but not the latest context, keep it as the accepted answer, and edit the question to indicate the limited context. For instance, if you asked "Can I run apps so they take up the full screen" under Leopard, the answer, in general was "No, there is no generic full-screen mode." Lion comes out, and now there is. Your question and its answer are still useful for someone running Lion, so edit the question to indicate "prior to OS X 10.7, can I run apps so they take up the full screen."
For released, versioned software, this strikes me as far and away the most appropriate way to go. On the other hand, in your case, the software you describe is an online service; the fact that something worked or did not work in previous versions is sadly not helpful, as the current behavior of the system applies to all users. In this case, the answer is no longer correct. Were it me, I would not un-accept until a more current answer arrives to replace it, but I would point out in a comment the changing circumstances, and perhaps edit the original question also.
