How to 'no-fill' empty cell that has been highlighted before?

i have code like below. This code will highlight the cell if meet condition. But it also highlight empty cell too.
My problem is to 'no-fill' the highlighted empty cell.
Below is the code sample



If processrow > 0 Then

yearidx = Year(.Cells(i, "B").value) - Application.Min(target.Rows(1))
monthidx = Month(.Cells(i, "B").value)
If Application.CountA(target.Rows(processrow)) > 1 Then

processrow = processrow + 1
target.Rows(processrow).Insert
End If

targetcol = yearidx * 12 + monthidx + 1
target.Cells(processrow, targetcol).value = .Cells(i, "C").value
target.Cells(processrow, targetcol).Interior.ColorIndex = 3



End If

change last line above to:

oops, that should have been: