A sub who did not timely send and serve a preliminary notice to the owner and the GC CANNOT legally file a mechanic’s lien on a project. The sub’s only recourse would be against the GC who hired them not against the owner or the property. I generally write a strong demand letter to the sub demanding that they release the lien due to their lack of a preliminary notice and threaten them with legal action, which usually works. I’m happy to answer any questions you have about this.