Order unanimously reversed, without costs, and motion denied. Memorandum: Time and again we have held that conditional orders of preclusion for failure to serve a bill of particulars may not be disregarded with impunity, and that in the absence of extraordinary and exceptional circumstances it is an abuse of discretion by Special Term to grant relief from such an order (Dent v Baxter, 37 A.D.2d 908). In addition, "Excuses for avoidable delay are insufficient which merely lay the delay at the door of the plaintiff himself, his lawyer of record, trial counsel, other associated counsel, or employees of any of the lawyers". (Sortino v Fisher, 20 A.D.2d 25, 29; see, also, Williams v Mallinckrodt Chem. Works, 42 A.D.2d 1044.) Since plaintiffs failed to meet their burden of explanation for neglect, other than overextension of counsel in professional commitments undertaken by him, it was an improvident exercise of discretion to vacate the orders of preclusion.