I am a subcontractor. The 45day window from "start date" has passed. I am still with in a few days of the commencement of the work. Have I missed the opportunity to be able to file a lien?
Your question is unclear. If you are within a few days of commencement of the work, then by definition you are inside of 45 days of "first furnshing." The 45 day deadline runs from when you first furnish services, not when you "should" have started under your contract.