Why will one wheel not move on zero turn mower?

One wheel on a zero-turn mower may not move due to a variety of reasons, including a malfunctioning wheel motor, low hydraulic fluid levels, or a problem with the drive belt. Additionally, a stuck or damaged wheel assembly can prevent movement. It's also possible that there is an issue with the control system or linkage that affects the operation of that wheel. Regular maintenance and inspections can help identify and resolve these issues.