There are conflicting rules in the 4 departments of New York.  In legal malpractice, it is plaintiff’s obligation to demonstrate that a hypothetical judgment could be collected in a legal malpractice case in the 2d, 3d and 4th departments.  In the First Department, it is an affirmitive defense for defendant to prove.

Here is a procedural case  from the 4th Department on the issue. Williams v Kublick
2007 NY Slip Op 04932 Decided on June 8, 2007 Appellate Division, Fourth Department .

"We conclude that Supreme Court erred in granting defendants’ motion, and we therefore modify the order accordingly. In granting the motion, the court determined, inter alia, that defendants established as a matter of law that plaintiff is unable to prove that defendants’ [*2]negligence is a proximate cause of plaintiff’s damages (see Robbins v Harris Beach & Wilcox, 291 AD2d 797, 798). That was error."

"A necessary element of a cause of action for legal malpractice is the collectibility of the damages in the underlying action (see McKenna v Forsyth & Forsyth, 280 AD2d 79, 82-83, lv denied 96 NY2d 720; cf. Lindenman v Kreitzer, 7 AD3d 830, 835). Here, regardless of whether the value of the property was improperly considered by the experts, we conclude that the otherwise conflicting opinions of the experts concerning the value of the assets of the joint venture precluded the court from determining as a matter of law that defendants established that plaintiff is unable to prove that he could collect damages in the underlying lawsuits (see generally Simmons v State Farm Mut. Auto. Ins. Co., 16 AD3d 1117; Herzog v Schroeder, 9 AD3d 669, 670)."