If the most up-voted answer is auto-accepted, can I duplicate the question to re-start a bounty with a highest value?
Hmm, that might become difficult. You would have to ask the question anew, see to it that it doesn't get closed as a duplicate, and if it survives 24 hours, you can post up a new bounty. The reputation from your old bounty will be definitely gone either way.
To prevent the current question from getting closed, you should mention the duplicate question and its history.
Duplicate questions are not encouraged/allowed on this system.
A bounty should have ABSOLUTELY NO bearing on that rule.
A bounty does not guarantee you receive a correct answer, nor does an accepted answer indicate that it is correct. An expired bounty does not "close" the question, i.e. the question itself can still receive answers.
So, there is no justification for asking the question again.
You can, but it's likely to be closed again. What I would be asking myself, before re-posting a bounty'd question, is:
What has fundamentally changed in the world of programming that makes my previously unanswerable question answerable?
If you can identify that key difference then by describing it you may avoid closure due to duplicates.
Keep in mind, though, that the system is meant to avoid duplication primarily for the reason that we don't want people to have to read 20 questions and their related answers before finding the real answer - all the answers to a given question should appear under one "parent" question. Purposefully duplicating something breaks that.
However, I've seen this work in some cases, for instance:
- Re-asking a question after a year or a new software/compiler/OS/etc release
- Re-asking the question with new information and a slight, but distinct, change in direction
- Re-asking the question more generally (ie, "I can't seem to resolve this. Help me take a step back and examine the problem from a different angle, here's some more information about what I'm really trying to accomplish.")
- Re-asking the question more specifically - narrow the focus so you get a definite "Yes, here's how" or "No, that is unimplementable", although it's hard to prove a negative, so even this is risky because you may still be left with doubts, and a desire to continue re-asking the same question over and over and over and over and STACKOVERFLOW^%#$&(&^(
But don't be unhappy if your new question is closed as a duplicate - that close reason exists for a good purpose. Keep in mind that bounties are not meant to guarantee an answer, only to feature the question for a limited time and encourage some people to consider working harder to find the answer for you.
Guys are working on it as say here