A party seeking to vacate a default in opposing a motion must demonstrate both a reasonable excuse for the default and a potentially meritorious opposition to the motion. The determination of what constitutes a reasonable excuse lies within the sound discretion of the trial court. In making its determination, the court may excuse a delay or default resulting from law office failure. However, law office failure should not be excused where a default results not from an isolated, inadvertent mistake, but from repeated neglect, or where allegations of law office failure are vague, conclusory, and unsubstantiated.. Mere neglect is not a reasonable excuse.
Here, in support of her motion, the plaintiff' submitted affirmations of her attorney and her treating physician, but they failed to set forth a detailed and credible explanation for the plaintiff's failure to oppose the defendants' motion. The plaintiff's claim of law office failure was vague, conclusory, and constituted mere neglect, and did not establish a reasonable excuse for the default. Furthermore, the plaintiff failed to demonstrate a reasonable excuse for the lengthy delay in moving to vacate the default.
Kyung Aye Yoon v. Haktung Lam, NY Slip Op 06731 (2d Dep't December 27, 2023)