Excel VBA Code error, when using Number Increment (CTRL Drag)

I have added a VBA code to my excel, what it does is automatically writes the rest of the number (For eg: When I write 2 and hit enter it will take the number above it and fill it to 990112 [see img])

This works fine when every number is typed, but When I use Auto Increment (CTRL + Drag) it throws an error

This is my VBA Code

Private Sub Worksheet_Change(ByVal Target As Range)
Dim oldText  As String, aboveText As St开发者_运维百科ring, newText As String
    If Target.Column = 3 Then
        oldText = Target.Text
        aboveText = Target.Cells(0, 1).Text

        If aboveText <> "DESIGN" Or Target.Text <> "" Then

            If Len(aboveText) = 6 And Len(oldText) < 6 And Len(oldText) >= 1 Then
                Application.EnableEvents = False
                newText = Left(aboveText, 6 - Len(oldText)) + oldText
                Target.Value = newText
                Application.EnableEvents = True
            End If

        End If

    End If

End Sub

Change

If Target.Column = 3 Then

to

If Target.Column = 3 And Target.Cells.Count = 1 Then

You're trying to get the Text property of a multi-cell range ("Target" in that situation is C6:C7). The new line will ensure that you are only changing one cell.