I filed a lien on 9/14/17 and the homeowner was able to close on his house this week
Oct 12, 2017
If an otherwise valid lien was filed prior to the closing and the title company just overlooked it, a lien claimant is generally allowed to proceed as s/he otherwise would, and could file an enforcement/foreclosure action against the property.
In a successful suit, the new owner would be forced to pay (or the property would be sold) to satisfy the claim. However, the new property owner would likely have a claim against the title insurance company (and the previous owner), and would bring those parties into the suit - where they may be forced to pay instead of the current property owner.