A process is provided for producing xylene by transalkylation including introducing sulfur into a reactor containing a catalyst system prior to first introduction of hydrocarbon feedstock into the reactor; introducing hydrocarbon feedstock into the reactor upon the concentration of sulfur downstream of the catalyst system meeting a predetermined sulfur breakthrough concentration; continuing sulfur introduction for a period of time after first introducing hydrocarbon feedstock into the reactor; reducing the concentration of sulfur introduced upon ΔT decreasing to or below a predetermined sulfur reduction threshold; and discontinuing sulfur introduction upon ΔT decreasing to or below a predetermined sulfur shutoff threshold.