Validation
Dim intSearch As Integer, varX As Variant
intSearch = 1
varX = DLookup("[CompanyName]", "Shippers", _
"[ShipperID] = '" & Me.YourTextBox & "'")
If varX > 2 Then
MsgBox("Too many")
Me.YourTextBox = ""
End If
Is CompanyName a field? I am assuming Shippers is the table name...