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- Where should I post follow-up questions? 7 answers
How to ask a question if it is a continuation of a question I asked before?
Should I edit my question and ask, or ask that as a new question?
Ask a new question. If necessary, you can add a link to the old question to provide background information. Try to keep your new post self-contained though.
The old question was once a question for you. If someone else has the same question, that person may not be helped by the new question that has taken the old question's place.
Also, answers to the old question may not be answers to the new question, and loose their context.
If your existing question is answered but as a result your now realise there are new, additional problems then that is a new question and should be asked separately (you can link to the original question to give background but the question must "stand alone"). This is an appropriate thing to do for several reasons;
On the other hand if it's simply a clarification to the current question then edit that in