A New York appeals court on Thursday dismissed a $42 million malpractice claim brought by the town of North Hempstead, N.Y., against Winston & Strawn, likely ending a battle that ensued when the town was socked with a $32 million verdict after a failed waste transfer venture.

In a unanimous ruling, the Appellate Division, 2nd Department, found that Winston & Strawn, the Chicago-based firm, could not be held liable for exercising its professional judgment. It added that the town had not supported charges that the firm had acted in its own self-interest because of an alleged conflict of interest.