Can a contractor file a lien for unfinished work?

I agree with Mr. Weiner that the contractor is jumping the gun in asserting his lien rights. 

That being said, when the contractor completes the work and you make final payment, be sure to request and receive (1) a Full Unconditional Waiver of Lien; and (2) an executed Release and Discharge of Lien, which should be recorded with the Register of Deeds.