Not all quiet title actions “clear title” completely. Some states have a quiet title action for the purpose of clearing a "particular, known" claim, title defect, or perceived defect. Contrast title registration which settles all title issues, both known and unknown. Quiet title actions are always subject to attack and are particularly vulnerable to jurisdictional challenges, both subject matter and personal, even years after final court decree in the action. It usually takes 3–6 months depending on the state where it is done.