Ordered that the order is affirmed insofar as appealed and cross-appealed from, without costs or disbursements.
“In an action to recover damages for legal malpractice, a plaintiff must demonstrate that the attorney ‘failed to exercise the ordinary reasonable skill and knowledge commonly possessed by a member of the legal profession’ and that the attorney’s breach of this duty proximately caused plaintiff to sustain actual and ascertainable damages ... To establish causation, a plaintiff must show that he or she would have prevailed in the underlying action or would not have incurred any damages, but for the lawyer’s negligence” (Rudolf v Shayne, Dachs, Stanisci, Corker & Sauer, 8 NY3d 438, 442 [2007] [citations omitted]). “For a defendant in a legal malpractice action to succeed on a motion for summary judgment, evidence must be submitted in admissible form establishing that the plaintiff is unable to prove at least one of [the] essential elements [of legal malpractice]” (Shopsin v Siben & Siben, 268 AD2d 578 [2000]; see Ippolito v McCormack, Damiani, Lowe & Mellon, 265 AD2d 303 [1999]).
The defendant failed to prove his prima facie entitlement to judgment as a matter of law since he did not demonstrate that the plaintiffs are unable to prove one of the essential elements of their malpractice claim (see Shopsin v Siben & Siben, 268 AD2d 578 [2000]). Similarly, the plaintiffs were not entitled to summary judgment since questions of fact exist regarding the malpractice claim (see Avery v Sirlin, 26 AD3d 451 [2006]; Maddux v Schur, 16 AD3d 873 [2005]).
Accordingly, the Supreme Court properly denied the respective motions for summary judgment (see Alvarez v Prospect Hosp., 68 NY2d 320 [1986]). Spolzino, J.P., Santucci, Angiolillo and Dickerson, JJ., concur.