I'm using a drop down box that contains 1000 different choices. I'm using the same drop down box in 400 places on 8 sheets in a workbook. I want to make sure the same value is not used more than once. I've tried usine the =if(or(F9=F11,F9=F13,F9=F15,F9=F17,F9=F19......)"U sed", "OK"). But it will not let me use more than 32 values. How do i compare the 400 different cells to one to make sure the value is not picked more than once?