Bonjour,
Ci-contre votre code corrigé :
Private Sub ComboBox1_Change()
Dim i&, Y&, bb()
If Me.ComboBox1.ListIndex = -1 Then Exit Sub
Y = 0
For i = 1 To Range("A" & Rows.Count).End(xlUp).Row
If Cells(i, 2) = Me.ComboBox1 Then
ReDim Preserve bb(Y)
bb(Y) = Cells(i, 1)
Y = Y + 1
End If
Next i
Me.ComboBox2.List = Application.Transpose(bb)
End Sub
Cdlt,