Bonjour,
A tester :
Sub Test()
Dim Plage As Range
Dim I As Long
With Worksheets("Feuil1"): Set Plage = .Range(.Cells(2, 1), .Cells(.Rows.Count, 1).End(xlUp)): End With
For I = Plage.Count To 1 Step -1
If Len(Plage(I, 1).Value) < 12 Then Plage(I, 1).Delete
Next I
End Sub