Have saved book in full macro mode (.xlsm) but the sheet_change event will
only run once and then nothing.Using data validation and comparing the value
of target cell and then offsetting. Have remmed all in the event to only
leave 1 range to no avail. Very confusing that the code will only run for the
first sheet change andthen nothing until it is closed and re-opened.
Some code below.

If Not Intersect(Target, Range("D8:M38")) Is Nothing Then
If Target.Offset(0, -1).Value = Range("P28") Then
If Target.Value < 0 Then
If Target.Value < Range("Q28").Value Then
MsgBox Range("P28") & " cannot work before " &
Range("Q28")
End If
End If
End If
End If

Ideas?