Copier automatiquement une colonne horizontale en verticale ss doublon

 quand tu insères une procédure, ça sera plus lisible :).
Une solution possible :

[code]
Sub Transposition_Nom()
Dim i As Long, d As Object
Set d = CreateObject("scripting.dictionary")
With Sheets("Feuille1")
For i = 1 To .[a65000].End(xlUp).Row
If .Cells(i, 1).Value <> "" Then d(.Cells(i, 1).Value) = ""
Next i
End With
Sheets("Feuille2").[a1].Resize(1, d.Count).Value = d.keys
End Sub

Private Sub Workbook_Open()
Dim i As Long, d As Object
Set d = CreateObject("scripting.dictionary")
With Sheets("Feuille1")
For i = 1 To .[a65000].End(xlUp).Row
If .Cells(i, 1).Value <> "" Then d(.Cells(i, 1).Value) = ""
Next i
End With
Sheets("Feuille2").Rows(1).ClearContents
Sheets("Feuille2").[a1].Resize(1, d.Count).Value = d.keys
End Sub

Private Sub Workbook_Open()
Dim i As Long, d As Object, c As Variant
Set d = CreateObject("scripting.dictionary")
With Sheets("Feuille1")
For i = 1 To .[a65000].End(xlUp).Row
If .Cells(i, 1).Value <> "" Then d(.Cells(i, 1).Value) = ""
Next i
End With
Sheets("Feuille2").Rows(1).ClearContents
i = 1
For Each c In d.keys
Sheets("Feuille2").Cells(1, i) = c
i = i + 2
Next c
End Sub