Auto Inserting MS Office Username on Event Change

I have a shared spreadsheet that uses a column with a validation list. I want to be able to take the MS Office Username contained in Tools > Options to be put into a cell A1 when changing the value of A2.

Is it possible?

Right-click on the sheet tab, select view code, and copy and paste the following:

Private Sub Worksheet_SelectionChange(ByVal Target As Excel.Range)
    Set Target = Cells(2, 1)
    Cells(1, 1).Value = ""
    If Target.Value <> "" Then Cells(1, 1).Value = Application.UserName
End Sub

This will enter the MS Excel user name in cell A1 whenever cell B1 is anything except blank. Is this what you were looking for?

Will this work for the range of a column or is it cell specific? Other than that, it's exactly what I was inquiring about. Thanks!

For a range of cells, you would need a little extra code:

Private Sub Worksheet_SelectionChange(ByVal Target As Excel.Range)
    Dim rng As Range
    Set Target = Range("A2:A10")
    Cells(1, 1).Value = ""
    For Each rng In Target
        If rng.Value <> "" Then
        Cells(1, 1).Value = Application.UserName
        End If
    Next rng
End Sub

You can change the red range above to suit your needs.

Thanks again. I tried the code and it works, but puts the value in a singular specific field. I don't think I'm explaining myself correctly.

For every cell in the range (let's say A3:A1501) that changes to Y, I need the corresponding cell in B3:B1501 to change to the username.

thanks again