Betinget lås af enkelte celler

Dim flag As Boolean              '<--
Private Sub Worksheet_Change(ByVal Target As Range)
Dim tar As String

    If Not Intersect(Target, Range("B8:B10")) Is Nothing And flag = False Then
        flag = True '<--
       
    tar = Target.Address
    On Error GoTo err

    Select Case tar
        Case Is = "$B$8"
        If Not IsEmpty(Target.Offset(1, 0)) _
        Or Not IsEmpty(Target.Offset(2, 0)) Then
        Target = ""
        End If
       
    Case Is = "$B$9"
        If Not IsEmpty(Target.Offset(-1, 0)) _
        Or Not IsEmpty(Target.Offset(1, 0)) Then
        Target = ""
        End If

    Case Is = "$B$10"
        If Not IsEmpty(Target.Offset(-1, 0)) _
        Or Not IsEmpty(Target.Offset(-2, 0)) Then
        Target = ""
        End If
       
    Case Else
        Exit Sub
    End Select
err:
End If
        flag = False            '<--
End Sub