Sub Do_It()
Application.ScreenUpdating = False
With ActiveSheet
f_max = .Cells(.Rows.Count, "F").End(xlUp).Row
For f = 2 To f_max
chk_f = .Cells(f, 6)
ff = WorksheetFunction.CountIf(.Range("F2:F" & f_max), chk_f)
bg = xlNone
msg = "No"
If ff > 1 Then
bg = 15
msg = "Yes"
End If
.Cells(f, 6).Interior.ColorIndex = bg
.Range("CF" & f) = msg
Next f
.Range("F1").Select
End With
Application.ScreenUpdating = True
End Sub
with Sheets("KPI")