How do I ignore the first row in an Excel macro that deletes all rows based on a criteria?

Question

This macro is designed to compare the data in column C and D and if C does not match D in a certain row, it deletes the entire tow. The problem is that it deletes the header

Answer 1

you can avoid loops:

Sub deleteNonMatchingRows()
    With Range("C2", Cells(Rows.Count, "C").End(xlUp)) ' reference column C cells from row 2 doen to last not empty one
        With .Offset(, .Parent.UsedRange.Columns.Count) ' reference referenced range offset by active sheet used range columnns (to be sure you'r not overwriting already filled cells)
            .FormulaR1C1 = "=IF(RC3<>RC4,1,"""")" ' have referenced cells show a "1" if corresponding cells in column C and D match
            .SpecialCells(xlCellTypeFormulas, xlNumbers).EntireRow.Delete ' delete all rows whose referenced column formula result is a number
            .ClearContents ' clear referenced range
        End With
    End With
End Sub

Answer 2

Deletion of a row is an operation that takes quite some time. Thus, it is a good idea to make all deletions at once, uniting all rows to be deleted in a specific range wholeRange:

Option Explicit

Public Sub DeleteNonMatchingRows()

    Dim LastRow As Long
    LastRow = Cells(Rows.Count, "C").End(xlUp).Row

    Dim wholeRange  As Range
    Dim iRow As Long
    For iRow = LastRow To 2 Step -1
        If Range("C" & iRow) <> Range("D" & iRow) Then
            If wholeRange Is Nothing Then
                Set wholeRange = Rows(iRow)
            Else
                Set wholeRange = Union(wholeRange, Rows(iRow))
            End If
        End If
    Next iRow

    If Not wholeRange Is Nothing Then
        wholeRange.Select       'delete this row
        Stop                    'delete this row
        wholeRange.Delete
    End If

End Sub

Once you run the code, it will stop on the Stop line. You will be able to see the range, which is to be deleted. The range will be selected. Once you see it, it is a good idea to delete the two rows, mentioned in the comments, you are not going to need them any more.

Answer 3

If you use a descriptive variable naming, eg. rename i into iRow you will never forget that this is your row counter, that is counting from row 9999 to row 1 in For iRow = 9999 To 1 Step -1. So you need to change the 1 into a 2 to omit the first row.

I recommend to use a dynamic start for your loop that automatically finds the last used row. This prevents unnecessary loop steps and you don't need to increase it for larger worksheets.

Option Explicit

Public Sub DeleteNonMatchingRows()
    Dim LastRow As Long
    LastRow = Cells(Rows.Count, "C").End(xlUp).Row 'find last used row in column C

    Dim iRow As Long
    For iRow = LastRow To 2 Step -1 
        If Range("C" & iRow) <> Range("D" & iRow) Then
            'Range("C" & iRow).EntireRow.Delete
             Rows(iRow).Delete 'directy delete a row
        End If
    Next iRow
End Sub