Abstract: The invention relates to an apparatus for detecting sheet misfeed from a multi-tray sheet feeder. The thickness of the first sheet fed from each tray is detected by a common sensor and a thickness value is placed in memory for that tray. Each sheet subsequently fed from the same tray is detected by the common sensor and the thickness value sensed is compared with the thickness value in memory for that tray. If the values match, then only one sheet has been fed from the tray. If the thickness value is more that the thickness value in memory for that tray, then that indicates that more than one sheet has left the tray and the system is shut down to enable an operator to correct the situation. When a tray is reloaded, the thickness value in memory for the sheets previously loaded in the tray is erased and the first sheet fed from the reloaded tray is sensed and a thickness value for that sheet is placed in memory for the reloaded tray.