Not necessarily. It depends on a few factors: (1) Are there any other witnesses or forms of admissible evidence available from which the subject events could be established? (2) Is the reason that the plaintiff cannot recall the accident because it is - medically speaking - impossible for him to do so? If so, he may be entitled to a special instruction that would lessen his burden of proof, and in some circumstances, shift the burden of proof in the case from the plaintiff to the defendant.

For additional information on this topic, also known as the "Noseworthy doctrine," please see "What NY Courts Will Do When a Plaintiff Doesn't Remember the Accident."
Jonathan Cooper
Connect with me
Non-Compete, Trade Secret, Unfair Competition and School Negligence Lawyer