Locing collums

[Medinukas]

Hello I desperetly need help work work.
I need to lock a column if another column has data entered and vise versa
Example I have a column A and B if enter any data in column A then I can't enter any data in column B and vise versa Plz help someone?

 

[mumps]

If you use that approach, you don't need to unlock or protect the sheet. Follow the steps I described in Post #2 to paste this macro.

Private Sub Worksheet_Change(ByVal Target As Range)
    If Intersect(Target, Range("A:A,B:B")) Is Nothing Then Exit Sub
    Select Case Target.Column
        Case Is = 1
            If Target = Target.Offset(0, 1) Then
                MsgBox ("You cannot enter a duplicate value.")
            End If
        Case Is = 2
            If Target = Target.Offset(0, -1) Then
                MsgBox ("You cannot enter a duplicate value.")
            End If
    End Select
End Sub