a second test, in removing the quotes, think as should be for defined ranges,
gets a different error.

'im testB1 As String
testB1 = Range("B1") 'caps


Set isect = Intersect(Target, Range(testB1, G1, G2, G3, G4, dateC4))
'error variable not defined
'without quotes: wrong number of arguments, or invalid property assignment

'Set isect = Intersect(Target, Range("A1, M1, X1")) 'orig sample
If Not isect Is Nothing Then
With Target
If .Cells.Count 1 Then Exit Sub
If .HasFormula Then Exit Sub
'On Error GoTo ErrHandler
Application.EnableEvents = False
Target = UCase(Target)
End With
End If
'ErrHandler:
Application.EnableEvents = True
End Sub